diff-index.c: "git diff" has no need to read blob from the standard input

diff --git a/RelNotes b/RelNotes
index e5de2fa02b2a5eab1252868dd5719206d2a387fa..fb9320b14baeae5fdb759a99e7edb77546cd5bc1 120000 (symlink)
--- a/RelNotes
+++ b/RelNotes
@@ -1 +1 @@
-Documentation/RelNotes-1.5.1.6.txt
\ No newline at end of file
+Documentation/RelNotes/1.7.6.6.txt
\ No newline at end of file