pretty: handle broken commit headers gracefully

diff --git a/RelNotes b/RelNotes
index 136c1b6afa6bc9cee85b018cd5df66c639c3fc91..7a99a15f2fd9141247b100eb9a5d0b9b88b0f2b9 120000 (symlink)
--- a/RelNotes
+++ b/RelNotes
@@ -1 +1 @@
-Documentation/RelNotes-1.7.1.1.txt
\ No newline at end of file
+Documentation/RelNotes/1.8.2.1.txt
\ No newline at end of file