Documentation: user-manual: "git commit -a" doesn't motivate .gitignore

"git commit -a" ignores untracked files and follows all tracked
files, regardless of whether they are listed in .gitignore.  So
don't use it to motivate gitignore.

Signed-off-by: Jonathan Nieder <jrnieder@uchicago.edu>
Acked-by: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/user-manual.txt

@@ -1128,8 +1128,8 @@ This typically includes files generated by a build process or temporary
 backup files made by your editor. Of course, 'not' tracking files with git
 is just a matter of 'not' calling "`git-add`" on them. But it quickly becomes
 annoying to have these untracked files lying around; e.g. they make
-"`git add .`" and "`git commit -a`" practically useless, and they keep
-showing up in the output of "`git status`".
+"`git add .`" practically useless, and they keep showing up in the output of
+"`git status`".
 
 You can tell git to ignore certain files by creating a file called .gitignore
 in the top level of your working directory, with contents such as: