update help text for -N

With -N, just parse arguments and ignore the file.

Change readme2index.sh version from "0.1 2023-12-10"
to "0.2 2023-12-29".  The previous change in
commit d5c4171d73
forgot to update the version number.

inc/md2html.cfg

@@ -48,7 +48,7 @@
 #	-V		print version string and exit
 #
 #	-n		go thru the actions, but do not update any files (def: do the action)
-#	-N		do not process file, just ignore the file (def: process the file)
+#	-N		do not process file, just parse arguments and ignore the file (def: process the file)
 #
 #	-d topdir	set topdir (def: if 'git rev-parse --is-inside-work-tree' is true, then
 #					 topdir is output of 'git rev-parse --show-toplevel')