Add missing docstrings

src/include-bash/pretty.sh

@@ -142,8 +142,8 @@ mkusage() {
     # usage patterns once and skip to them from any place where
     # you detect incorrect usage.
     #
-    local es=$EXIT_USAGE
-    local doexit=true
+    local es=$EXIT_USAGE    # our exit status
+    local doexit=true       # should we exit?
     while true; do case "$1" in
         -e) es="$2";            shift 2 || return 2 ;;
         -E) doexit=false;       shift        ;;