doc/git-reset: add reference to git-stash

The "Interrupted workflow" situation is a good example for using
git-stash.

Signed-off-by: Markus Heidelberg <markus.heidelberg@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-reset.txt

@@ -177,6 +177,8 @@ $ git reset                                       <3>
 <3> At this point the index file still has all the WIP changes you
     committed as 'snapshot WIP'.  This updates the index to show your
     WIP files as uncommitted.
++
+See also linkgit:git-stash[1].
 
 Reset a single file in the index::
 +