submodule: rewrite `module_clone` shell function in C

diff --git a/RelNotes b/RelNotes
index bcb4fb98ff925389797125283e40c6e397efc1fd..84a20c84c648cacea6b2cbdab43d36e92aaaa5c8 120000 (symlink)
--- a/RelNotes
+++ b/RelNotes
@@ -1 +1 @@
-Documentation/RelNotes/1.7.11.txt
\ No newline at end of file
+Documentation/RelNotes/2.6.0.txt
\ No newline at end of file