use skip_prefix to avoid repeating strings

diff --git a/RelNotes b/RelNotes
index 1af36eae21050a37bf71f2e1662c41066bc3c257..bf760914010786c830233effc8b96ddacfb114fd 120000 (symlink)
--- a/RelNotes
+++ b/RelNotes
@@ -1 +1 @@
-Documentation/RelNotes/1.7.10.5.txt
\ No newline at end of file
+Documentation/RelNotes/2.1.0.txt
\ No newline at end of file