Documentation: hooks: fix missing verb in pre-applypatch description

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/hooks.txt

@@ -28,10 +28,11 @@ The default 'applypatch-msg' hook, when enabled, runs the
 pre-applypatch
 --------------
 
-This hook is invoked by `git-am`.  It takes no parameter,
+This hook is invoked by `git-am`.  It takes no parameter, and is
-and is invoked after the patch is applied, but before a commit
+invoked after the patch is applied, but before a commit is made.
-is made.  Exiting with non-zero status causes the working tree
+
-after application of the patch not committed.
+If it exits with non-zero status, then the working tree will not be
+committed after applying the patch.
 
 It can be used to inspect the current working tree and refuse to
 make a commit if it does not pass certain test.