Add support for HLS versions >=0.2.2

[shaunplee]

Addresses issue #73 to support HLS >=0.2.2 while trying to retain existing behavior for everything else.

Also, I'm new to elisp and open source. Please let me know if I've done something wrong.

[shaunplee]

Perhaps no longer needed due to: haskell/haskell-language-server#243

[shaunplee]

Actually, this might eventually be needed, per the CHANGELOG in this commit
haskell/haskell-language-server@e44f618

This changes the configuration section from "languageServerHaskell" to "haskell" to align it with vscode-haskell-1.0.0. Whilst the old section is still supported for now, you should update your LSP configuration (which varies per client) from

{
  "languageServerHaskell": {
    "formattingProvider": "stylish-haskell"
  }
}

to

{
  "haskell": {
    "formattingProvider": "stylish-haskell"
  }
}