Documentation: cite git-am from git-apply

Users reading git-apply documentation may also be interested in git-am,
especially after receiving an email created with git-format-patch.  The
documentation for git-am already references git-apply.  Add the reverse.

Signed-off-by: Brad King <brad.king@kitware.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-apply.txt

@@ -26,6 +26,10 @@ with the `--cache` option the patch is only applied to the index.
 Without these options, the command applies the patch only to files,
 and does not require them to be in a git repository.
 
+This command applies the patch but does not create a commit.  Use
+linkgit:git-am[1] to create commits from patches generated by
+linkgit:git-format-patch[1] and/or received by email.
+
 OPTIONS
 -------
 <patch>...::
@@ -242,6 +246,12 @@ If `--index` is not specified, then the submodule commits in the patch
 are ignored and only the absence or presence of the corresponding
 subdirectory is checked and (if possible) updated.
 
+
+SEE ALSO
+--------
+linkgit:git-am[1].
+
+
 Author
 ------
 Written by Linus Torvalds <torvalds@osdl.org>