Documentation: update "stale" links for 1.5.2.2

Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Documentation/git.txt

@@ -41,9 +41,11 @@ unreleased) version of git, that is available from 'master'
 branch of the `git.git` repository.
 Documentation for older releases are available here:
 
-* link:v1.5.2/git.html[documentation for release 1.5.2]
+* link:v1.5.2.2/git.html[documentation for release 1.5.2.2]
 
 * release notes for
+  link:RelNotes-1.5.2.2.txt[1.5.2.2],
+  link:RelNotes-1.5.2.1.txt[1.5.2.1],
   link:RelNotes-1.5.2.txt[1.5.2].
 
 * link:v1.5.1.6/git.html[documentation for release 1.5.1.6]