fast-import: clarify documentation of "feature" command

diff --git a/RelNotes b/RelNotes
index 2ebf251ddf3c4091ad6b55aef86bfccbd1c612f2..2e4322a073d72f242a56bc2e00c9aa84ff73806c 120000 (symlink)
--- a/RelNotes
+++ b/RelNotes
@@ -1 +1 @@
-Documentation/RelNotes-1.6.1.1.txt
\ No newline at end of file
+Documentation/RelNotes/1.7.0.9.txt
\ No newline at end of file