doc: check for absence of the form --[no-]parameter

For better searchability, this commit adds a check to ensure that parameters
expressed in the form of `--[no-]parameter` are not used in the
documentation.  In the place of such parameters, the documentation should
list two separate parameters: `--parameter` and `--no-parameter`.

Signed-off-by: Jean-Noël Avila <jn.avila@free.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-range-diff.adoc

@@ -96,7 +96,8 @@ diff.
 --remerge-diff::
 	Convenience option, equivalent to `--diff-merges=remerge`.
 
---[no-]notes[=<ref>]::
+--notes[=<ref>]::
+--no-notes::
 	This flag is passed to the `git log` program
 	(see linkgit:git-log[1]) that generates the patches.