Support HLS 0.2.2

[Ailrun]

Now HLS 0.2.2 uses the field name haskell instead of languageServerHaskell.

See https://github.com/haskell/haskell-language-server/releases/tag/0.2.2.

[shaunplee]

@Ailrun This is literally my first time trying to hack elisp. This seems to work for me (tried with HLS 0.2.2 and old version of HIE):

https://github.com/shaunplee/lsp-haskell

Can you give it a try before I submit a pull request, so that we have N>1?

[Ailrun]

Great, I will try it out and let you know as soon as I can access my PC.

[shaunplee]

Perhaps no longer needed due to a change in HLS? haskell/haskell-language-server#243

[Ailrun]

Close this as HLS now supports languageServerHaskell again.