main/vim: upgrade to 8.2.2852

This includes a fix [0] for building vim with our new default LDFLAGS
value. posix-shell-redirection.patch has also been applied upstream.
Decided to upgrade vim instead of backporting the aforementioned patch
since backporting would require regenerating the automake files.

[0]: https://github.com/vim/vim/commit/761ead497feff5fd259c9f6ca76d184bb8755373