ls-remote doc: don't encourage use of branches-file

One outdated example encourages the use of $GIT_DIR/branches files.
Replace it with an equivalent example using a remote.

Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-ls-remote.txt

@@ -70,8 +70,8 @@ EXAMPLES
 	$ git ls-remote http://www.kernel.org/pub/scm/git/git.git master pu rc
 	5fe978a5381f1fbad26a80e682ddd2a401966740	refs/heads/master
 	c781a84b5204fb294c9ccc79f8b3baceeb32c061	refs/heads/pu
-	$ echo http://www.kernel.org/pub/scm/git/git.git >.git/branches/public
-	$ git ls-remote --tags public v\*
+	$ git remote add korg http://www.kernel.org/pub/scm/git/git.git
+	$ git ls-remote --tags korg v\*
 	d6602ec5194c87b0fc87103ca4d67251c76f233a	refs/tags/v0.99
 	f25a265a342aed6041ab0cc484224d9ca54b6f41	refs/tags/v0.99.1
 	c5db5456ae3b0873fc659c19fafdde22313cc441	refs/tags/v0.99.2