Merge branch 'jc/am-whitespace-doc'

"git am --help" now tells readers what actions are available in
"git am --whitespace=<action>", in addition to saying that the
option is passed through to the underlying "git apply".

* jc/am-whitespace-doc:
  doc: add shortcut to "am --whitespace=<action>"

Author: gitster

Documentation/git-am.txt

@@ -128,6 +128,9 @@ include::rerere-options.txt[]
 	These flags are passed to the 'git apply' (see linkgit:git-apply[1])
 	program that applies
 	the patch.
++
+Valid <action> for the `--whitespace` option are:
+`nowarn`, `warn`, `fix`, `error`, and `error-all`.
 
 --patch-format::
 	By default the command will try to detect the patch format

apply.c

@@ -77,7 +77,8 @@ static int parse_whitespace_option(struct apply_state *state, const char *option
 		return 0;
 	}
 	/*
-	 * Please update $__git_whitespacelist in git-completion.bash
+	 * Please update $__git_whitespacelist in git-completion.bash,
+	 * Documentation/git-apply.txt, and Documentation/git-am.txt
 	 * when you add new options.
 	 */
 	return error(_("unrecognized whitespace option '%s'"), option);