Problem:
- Windows users can't use terminfo to configure their terminal
capabilities. #37274
- Terminfo definitions sometimes get out of date or are simply
inaccurate.
- Eventually, we may want to drop terminfo, relying primarily on
built-in definitions. Users will still need some flexibility.
Solution:
Support $NVIM_TERMDEFS environment variable, which is JSON data that
defines "terminfo" definitions that override our builtin terminfo.
84d5c5f4bf
