correct spelling: an URL -> a URL

Signed-off-by: Jim Meyering <meyering@redhat.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/perl/Git.pm b/perl/Git.pm
index f7ce511..497f420 100644
--- a/perl/Git.pm
+++ b/perl/Git.pm
@@ -691,7 +691,7 @@
 contains the tag object while a C<refname^{}> entry gives the tagged objects.
 
 C<REPOSITORY> has the same meaning as the appropriate C<git-ls-remote>
-argument; either an URL or a remote name (if called on a repository instance).
+argument; either a URL or a remote name (if called on a repository instance).
 C<GROUPS> is an optional arrayref that can contain 'tags' to return all the
 tags and/or 'heads' to return all the heads. C<REFGLOB> is an optional array
 of strings containing a shell-like glob to further limit the refs returned in