Fix broken links in the documentation

Also removed a duplicate link under "Script Reference".
Updating submodule(s).

 [nomail]
Merge branch 'fastpath'
Merge branch 'topic/dnthayer/doc-fix-links'

BIT-1076 #merged
Fix another function val reference counting bug.

Now that functions get unref'd in the val dtor in order to free mem of
unserialized functions, it's important to ref a function when creating a
val from a pre-existing function so it's not prematurely free'd.