tools: make nfdc smarter when the user asks for help

Now 'nfdc foo help', 'nfdc foo --help', and 'nfdc foo -h'
are all accepted as synonyms of 'nfdc help foo'.

Additionally, '--version' can be used in place of '-V'.

Change-Id: I070bb0ea9231a2642c40938377f1e9af2630b34e
Refs: #4503
diff --git a/docs/manpages/nfdc.rst b/docs/manpages/nfdc.rst
index 17824b8..d80d6dd 100644
--- a/docs/manpages/nfdc.rst
+++ b/docs/manpages/nfdc.rst
@@ -3,10 +3,10 @@
 
 SYNOPSIS
 --------
-| nfdc COMMAND ARGUMENTS
-| nfdc [-h]
-| nfdc -V
-| nfdc help COMMAND
+| nfdc COMMAND [ARGUMENTS] ...
+| nfdc help [COMMAND]
+| nfdc [-h|--help]
+| nfdc -V|--version
 
 DESCRIPTION
 -----------
@@ -25,11 +25,11 @@
 <ARGUMENTS>
     Arguments to the subcommand.
 
--h
-    Print a list of available subcommands.
+``-h`` or ``--help``
+    Print a list of available subcommands and exit.
 
--V
-    Print version number.
+``-V`` or ``--version``
+    Show version information and exit.
 
 EXAMPLES
 --------