git-show-ref: fix escaping in asciidoc source

diff --git a/RelNotes b/RelNotes
index 00e77229ddadcb8a13b10b693a96bd76a4cb9f33..fb9320b14baeae5fdb759a99e7edb77546cd5bc1 120000 (symlink)
--- a/RelNotes
+++ b/RelNotes
@@ -1 +1 @@
-Documentation/RelNotes-1.7.1.txt
\ No newline at end of file
+Documentation/RelNotes/1.7.6.6.txt
\ No newline at end of file