Reformat docstrings to 76 character width

As recommended by Shellfu style:

    https://github.com/AloisMahdal/shellfu/blob/master/notes/style.md

src/saturnin.sh.skel

 # Git commit hash of application source tree
 #
 # This is supposed to be set by your build scripts when building your
-# application.  The string is returned by calling your meta-command
-# with option --saturnin-app-git-hash.
+# application.  The string is returned by calling your meta-command with
+# option --saturnin-app-git-hash.
 #
 # Look for 'satcmd' template for a working example.
 #
 # Your application version
 #
 # This is supposed to be set by your build scripts when building your
-# application.  The string is returned by calling your meta-command
-# with options --version, --version-semver or  --saturnin-app-version.
+# application.  The string is returned by calling your meta-command with
+# options --version, --version-semver or  --saturnin-app-version.
 #
 # Look for 'satcmd' template for a working example.
 #
 #
 # Path where saturnin__conf should look for files
 #
-# If filename does not contain slash, it is looked up in each
-# (or all, based on strategy--see saturnin__conf() doc) path in this
-# list.  The list is colon-separated and non-dirs as well as
-# empty strings are silently ignored.
+# If filename does not contain slash, it is looked up in each (or all,
+# based on strategy--see saturnin__conf() doc) path in this list. The
+# list is colon-separated and non-dirs as well as empty strings are
+# silently ignored.
 #
 SATURNIN_CONF_PATH="${SATURNIN_CONF_PATH:-}"
 
 #
 # Expected config filename extension (for guessing from path head)
 #
-# If no filename to read is given, saturnin__conf() will guess
-# filename as the path head plus this suffix (e.g. `foo.ini` for
-# `saturnin__conf foo.bar.baz`)
+# If no filename to read is given, saturnin__conf() will guess filename
+# as the path head plus this suffix (e.g. `foo.ini` for `saturnin__conf
+# foo.bar.baz`)
 #
 SATURNIN_CONF_SUFFIX="${SATURNIN_CONF_SUFFIX:-.ini}"
 
 #
 # Directory where to look for subcommands
 #
-# Files here starting with $SATURNIN_LIBEXEC_PREFIX are considered subcommands
+# Files here starting with $SATURNIN_LIBEXEC_PREFIX are considered
+# subcommands
 #
 SATURNIN_LIBEXEC="${SATURNIN_LIBEXEC:-}"
 
 #
 # Subcommand file prefix
 #
-# This is recommended to be set to meta-command name plus dash.  For example,
-# if your meta-command is `mykit`, this should be set to `mykit-`.
+# This is recommended to be set to meta-command name plus dash.  For
+# example, if your meta-command is `mykit`, this should be set to
+# `mykit-`.
 #
 SATURNIN_LIBEXEC_PREFIX="${SATURNIN_LIBEXEC_PREFIX:-}"
 
     # Warn about bug in your software
     #
     # Issue warning using warn() from pretty but also add application
-    # version.  This is useful when an assertion in your application
-    # fails such that it is certain that there is a bug inside it.
+    # version.  This is useful when an assertion in your application fails
+    # such that it is certain that there is a bug inside it.
     #
-    # In such cases, it makes sense to print also version information
-    # to help users with reporting.
+    # In such cases, it makes sense to print also version information to
+    # help users with reporting.
     #
     local msg
     for msg in "$@";
     # File arguments
     # ==============
     #
-    # If omitted, *file* argument is inferred by taking part of
-    # kpath name before first dot and appending value of
-    # `$SATURNIN_CONF_SUFFIX`, (".ini" by default).
+    # If omitted, *file* argument is inferred by taking part of kpath name
+    # before first dot and appending value of `$SATURNIN_CONF_SUFFIX`,
+    # (".ini" by default).
     #
     # Each *file* argument is then processed as follows:
     #
-    #  *  `-` (single dash) is interpreted as reading from
-    #     STDIN.
+    #  *  `-` (single dash) is interpreted as reading from standard input.
     #
-    #  *  If argument contains slash, it is expanded as a regular
-    #     path (relative or absolute).
+    #  *  If argument contains slash, it is expanded as a regular path
+    #     (relative or absolute).
     #
-    #  *  Otherwise, it is taken as filename and searched for
-    #     in directories given in `$SATURNIN_CONF_PATH`.  (This can
-    #     yield more than one path, which is equivalent as if
-    #     all paths were provided.)
+    #  *  Otherwise, it is taken as filename and searched for in directories
+    #     given in `$SATURNIN_CONF_PATH`.  (This can yield more than one
+    #     path, which is equivalent as if all paths were provided.)
     #
-    #     Not all files expanded based on `$SATURNIN_CONF_PATH`
-    #     are read by default; reading is governed by "merge
-    #     strategy": the default strategy "first" reads only
-    #     the first existing file.
+    #     Not all files expanded based on `$SATURNIN_CONF_PATH` are read by
+    #     default; reading is governed by "merge strategy": the default
+    #     strategy "first" reads only the first existing file.
     #
-    #     "join" strategy on the other hand, means that any
-    #     files are simply concatenated and prefixed with
-    #     comment (visible only in raw mode) containing path
-    #     to the file.
+    #     "join" strategy on the other hand, means that any files are simply
+    #     concatenated and prefixed with comment (visible only in raw mode)
+    #     containing path to the file.
     #
-    #     This means that if a section is queried that is
-    #     present in both files, it is effectively concatenated
-    #     as well.
+    #     This means that if a section is queried that is present in both
+    #     files, it is effectively concatenated as well.
     #
     # Following calls are equivalent
     #
     #     saturnin__conf foo.bar.baz
     #     saturnin__conf foo.bar.baz foo.ini
     #
-    # and both result in reading of key *baz* from section *foo.bar*
-    # in file *foo.ini*, which is selected from *SATURNIN_CONF_PATH*.
-    # Should there be more foo.ini's, the first is selected.
-    # Using `-j` switch
+    # and both result in reading of key *baz* from section *foo.bar* in file
+    # *foo.ini*, which is selected from *SATURNIN_CONF_PATH*.  Should there
+    # be more foo.ini's, the first is selected.  Using `-j` switch
     #
     #     saturnin__conf -j foo.bar.baz
     #
-    # would cause all foo.ini's on *SATURNIN_CONF_PATH* be
-    # concatenated instead.
+    # would cause all foo.ini's on *SATURNIN_CONF_PATH* be concatenated
+    # instead.
     #
     local ig_mode               # retrieval mode
     local ig_query              # keypath or section name (when listing keys)
     #
     # Find all existing instances of sub-path $1 on $SATURNIN_CONF_PATH
     #
-    # Go through all elements of $SATURNIN_CONF_PATH, looking for file
-    # on sub-path $1.  Print each existing path, ignore rest.
+    # Go through all elements of $SATURNIN_CONF_PATH, looking for file on
+    # sub-path $1.  Print each existing path, ignore rest.
     #
     # If at least one path was found, return zero.  Otherwise, return one,
     # or more in case of error.
 
 saturnin__get() {
     #
-    # Show Saturnin Internal info by key $1 and exit
+    # Show Saturnin internal info by key $1 and exit
     #
-    # Key $1 can be whole `--saturnin-get-stuff` argument or just
-    # the part after `--saturnin-get-`.
+    # Key $1 can be whole `--saturnin-get-stuff` argument or just the part
+    # after `--saturnin-get-`.
     #
-    # This is aimed to help debugging and testing the app (or
-    # Saturnin itself) by showing packaging and deployment related
-    # info.
+    # This is aimed to help debugging and testing the app (or Saturnin
+    # itself) by showing packaging and deployment related info.
     #
     local key=${1#--saturnin-get-}
     case "$key" in
     #
     # Main meta-command entry function
     #
-    # After setting all mandatory environment variables, call this from
-    # your main meta-command script.
+    # After setting all mandatory environment variables, call this from your
+    # main meta-command script.
     #
     local subcommand
     test -n "$SATURNIN_CACHE_HOME"     || die "SATURNIN_CACHE_HOME is not set"
     #
     # Assemble SATURNIN_CONF_PATH from locations $@
     #
-    # For each location, print colon-delimited list of
-    # directories.  If location ends with "/ini.d", list of
-    # subfolders, sorted by C locale is printed--this allows
-    # for modular configuration.  Otherwise the location
-    # is printed.  Non-existent or non-directory locations
-    # are silently ignored.
+    # For each location, print colon-delimited list of directories.  If
+    # location ends with "/ini.d", list of subfolders, sorted by C locale is
+    # printed--this allows for modular configuration.  Otherwise the
+    # location is printed.  Non-existent or non-directory locations are
+    # silently ignored.
     #
     local location      # one location argument
     local path          # one path listed
     #
     # Run custom hook named $1 from respective configuration section
     #
-    # Will load joined multi-line key "hook.$SATURNIN_SUBCOMMAND.$1",
-    # and execute it as Bash code.
+    # Will load joined multi-line key "hook.$SATURNIN_SUBCOMMAND.$1" and
+    # unless syntax check fails, execute it as Bash code (in separate
+    # process).
     #
     local hname="$1"
     local hook_code
     #
     # Print contents of files specified in $@
     #
-    # Each argument means possible file candidate.  If candidate
-    # contains slash, it's treated as file path and is printed
-    # directly.  If it's single dash, standard input is copied.
+    # Each argument means possible file candidate.  If candidate contains
+    # slash, it's treated as file path and is printed directly.  If it's
+    # single dash, standard input is copied.
     #
-    # In all other cases, filename is searched in all elements
-    # of SATURNIN_CONF_PATH; output then depends on chosen $Strategy:
-    # with 'first' strategy, first existing file is printed, with
-    # 'join' strategy. all existing files are printed.
+    # In all other cases, filename is searched in all elements of variable
+    # SATURNIN_CONF_PATH; output then depends on chosen $Strategy: with
+    # 'first' strategy, first existing file is printed, with 'join'
+    # strategy, all existing files are printed.
     #
     local arg es
     es=0
     #
     # Convert newline-based list of paths to colon:based:list
     #
-    # Empty paths must not be included in the resulting list,
-    # so we need to drop them and also get the colons right.
+    # Empty paths must not be included in the resulting list, so we need to
+    # drop them and also get the colons right.
     #
     local idx=0     # current item index (zero-based)
     local path