WIP: Add ctrl-home and ctrl-end Win32 bindings

Similar to #2166, this tries to get Win32 bindings feeling a more native for me. i'll leave this PR open for a bit and collect more keybindings as i come with them or as they get submitted. i don't plan to wait very long because i miss ctrl-home and ctrl-end!

* [x] `ctrl-home` should go to the beginning of the file
* [x] `ctrl-end` should go to the end of the file