ENH: improve output formatting for usage information

- generalize output text wrapping, use for usage notes

- add -help-man option for generating manpage content for any OpenFOAM
  application or solver.

  bin/tools/foamCreateManpage as helper

bin/tools/foamCreateCompletionCache

@@ -140,7 +140,8 @@ HEADER
 #   -opt1         descrip
 #   -opt2 <arg>   descrip
 #   -help-full
-# Terminate parsing on first appearance of -help-full
+# Ignore -help-man (internal option).
+# Terminate parsing on first appearance of -help-full.
 # - options with '=' (eg, -mode=ugo) are not handled very well at all.
 # - alternatives (eg, -a, -all) are not handled nicely either,
 #   for these treat ',' like a space to catch the worst of them.
@@ -148,12 +149,15 @@ extractOptions()
 {
     local appName="$1"
     local helpText=$($appName -help-full 2>/dev/null | \
-        sed -ne 's/^ *//; /^$/d; /^[^-]/d; /^--/d;' \
+        sed -ne 's/^ *//; /^$/d; /^[^-]/d; /^--/d; /^-help-man/d;' \
             -e 'y/,/ /; s/=.*$/=/;' \
             -e '/^-[^ ]* </{ s/^\(-[^ ]* <\).*$/\1/; p; d }' \
             -e 's/^\(-[^ ]*\).*$/\1/; p; /^-help-full/q;' \
             )
 
+    # After this bit of sed, we have "-opt1" or "-opt2 <"
+    # for entries without or with arguments.
+
     [ -n "$helpText" ] || {
         echo "Error calling $appName" 1>&2
         return 1
@@ -163,8 +167,8 @@ extractOptions()
     local argOpts=($(awk '/</ {print $1}' <<< "$helpText"))
 
     # Array of options without args, but skip the following:
-    #     -help-compat -help-full
-    local boolOpts=($(awk '!/</ && !/help-(compat|full)/ {print $1}' <<< "$helpText"))
+    #     -help-compat -help-full etc
+    local boolOpts=($(awk '!/</ && !/help-/ {print $1}' <<< "$helpText"))
 
     appName="${appName##*/}"
     echo "$appName" 1>&2