Documentation: fix gitlinks

Signed-off-by: Jonathan Nieder <jrnieder@uchicago.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt
index ca13266..cbfc5d0 100644
--- a/Documentation/user-manual.txt
+++ b/Documentation/user-manual.txt
@@ -1303,7 +1303,7 @@
 $ git diff --theirs file.txt	# same as the above.
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-The linkgit:git-log[1] and gitk[1] commands also provide special help
+The linkgit:git-log[1] and linkgit:gitk[1] commands also provide special help
 for merges:
 
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