1. Add ale.setup and ale.setup.buffer for pure Lua configuration.
2. Update many global settings to use Booleans instead of numbers to
make types easiert to work with in Lua.
3. Radically reformat documentation and fix errors to make
documentation more usable for Neovim users.
fixes#1738
- Replace previous `hh_client` usage with LSP client
- Add `HHAST` linter
- Split Hack from PHP: Hack is increasingly diverging from PHP:
- Hack tools do not understand PHP
- Most PHP tools do not handle Hack code well (including vim's syntax
highightling files)
- http://github.com/hhvm/vim-hack now sets filetype to `hack`
