This commit add support for ink-language-server, which it does by
largely copying and pasting from the pure-language-server PR that was
merged recently.
The most interesting things to note are:
- ink-language-server is distributed upstream via npm, which is why we
search through node_modules
- With some coaxing, it can be installed globally - which is why we
search for a global binary.
- Ink is a funky language, and users will likely need to add
initialization options.
- I am not incredibly familiar with vimscript; and I may not have done
some of the buffer searching correctly.
