Update alternate search path for A.vim

This adds `include/private` to the A.vim search path. This is
a thing I use at work. I would like to not have any work specific code
in this repo but this is the only mechanism I think I can use to achieve
this.
Spelling updates for my personal spelling library.

Added some words from my spelling library. This should probably be moved
off into its own submodule that I could control privately.