fast-import: add a get-mark command

diff --git a/RelNotes b/RelNotes
index a479abbc60611a95d75a33b092a322cb5fa2832c..1addbec92533510e6e368c607deb36e504bbc438 120000 (symlink)
--- a/RelNotes
+++ b/RelNotes
@@ -1 +1 @@
-Documentation/RelNotes-1.7.2.1.txt
\ No newline at end of file
+Documentation/RelNotes/2.4.0.txt
\ No newline at end of file