Fix git-symbolic-ref typo in git.txt.

Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/Documentation/git.txt b/Documentation/git.txt
index 5f068c2..875d4877 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -422,7 +422,7 @@
 gitlink:git-send-email[1]::
 	Send patch e-mails out of "format-patch --mbox" output.
 
-gitlink:git-symbolic-refs[1]::
+gitlink:git-symbolic-ref[1]::
 	Read and modify symbolic refs.
 
 gitlink:git-stripspace[1]::