Add usage message to saturnin-conf

src/shellfu/saturnin.sh

         -K:*)   ig_mode=$1; ig_query=$2; shift 2; break ;;
         -S:*)   ig_mode=$1; ig_query=""; shift 1; break ;;
         -P:*)   ig_mode=$1; ig_query=""; shift 1; break ;;
-        .*:*)   warn "bad syntax: $*"; return 2 ;;
+        .*:*)   warn "bad syntax: $*"; _saturnin__conf_usage ;;
         *.*:*)  ig_mode=-e; ig_query=$1; shift 1; break ;;
-        *)      warn "bad syntax: $*"; return 2 ;;
+        *)      warn "bad syntax: $*"; _saturnin__conf_usage ;;
     esac done
     test -n "$ig_mode" || { warn "could not determine inigrep mode"; _saturnin__conf_usage; }
     debug -v ig_limit ig_query ig_mode Strategy
     #
     #
     #
-    mkusage "[options] [-e] SECTION.KEY [FILE...]"                             \
-            "[options] -r SECTION.KEY [FILE...]"                               \
-            "[options] -K SECTION [FILE...]"                                   \
-            "[options] -P [FILE...]"                                           \
-            "[options] -S [FILE...]"                                           \
+    PRETTY_USAGE="self=${0##*/} conf" \
+    mkusage "[options] [-e] SECTION.KEY [FNAME]"                               \
+            "[options] -r SECTION.KEY [FNAME]"                                 \
+            "[options] -K SECTION [FNAME]"                                     \
+            "[options] -P FNAME"                                               \
+            "[options] -S FNAME"                                               \
+        --                                                                     \
+            "Use inigrep to query config files."                               \
         -o                                                                     \
             "-j     join all files before applying query"                      \
             "-1     ensure single line is returned"                            \
             "-e     use normal mode (default)"                                 \
             "-r     use raw mode (preserves RHS whitespace and some comments)" \
             "-K     list available keys in SECTION"                            \
-            "-S     list available sections"                                   \
-            "-P     list available keypaths (SECTION.KEY)"                     \
+            "-S     list available sections in FNAME"                          \
+            "-P     list available keypaths (SECTION.KEY) in FNAME"            \
         --                                                                     \
-            "Uses inigrep to query config files.  SECTION is section name (may"\
-            "contain dots itself, KEY is key name.  Unless FILE is provided,"  \
-            "filename is inferred from SECTION (eg. 'foo.ini' if 'foo.bar' was"\
-            "sectionname) and searched in folders given in SATURNIN_CONF_PATH."\
-            "If FILE contains slash, no search is done and just single FILE is"\
-            "used instead."
+            "FNAME is filename, which is then searched on all paths specified" \
+            "in SATURNIN_CONF_PATH and depending on -j parameter, first one"   \
+            "wins or all are joined.  If FNAME contains slash, this search is" \
+            "not done and FNAME is taken as path to file that is then queried."\
+            ""                                                                 \
+            "If FNAME is omitted, it is inferred from SECTION (e.g. .'foo.ini'"\
+            "if 'foo.bar' was section name; note that section name may contain"\
+            "dot)."
 }
 
 _saturnin__nl2colon() {