Fix minor typo.

Signed-off-by: Jon Loeliger <jdl@jdl.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>

Documentation/git-show-branch.txt

@@ -141,7 +141,7 @@ it, having the following in the configuration file may help:
 
 ------------
 
-With this,`git show-branch` without extra parameters would show
+With this, `git show-branch` without extra parameters would show
 only the primary branches.  In addition, if you happen to be on
 your topic branch, it is shown as well.