completion: use "git -C $there" instead of (cd $there && git ...)

diff --git a/RelNotes b/RelNotes
index 03c996d22ac5e007157998aba981ab113cf1ad7c..277f28f953706b6de9fb1533e298985521d72996 120000 (symlink)
--- a/RelNotes
+++ b/RelNotes
@@ -1 +1 @@
-Documentation/RelNotes-1.6.3.4.txt
\ No newline at end of file
+Documentation/RelNotes/1.8.5.5.txt
\ No newline at end of file