Try both haskell-language-server-wrapper and haskell-language-server by default

[purefn]

Feature description

I'm using haskell.nix and its shellFor to supply HLS. haskell.nix does not provide the wrapper script, input-output-hk/haskell.nix#1776, just the exe. If there isn't a wrapper available, we should check to see if we can find a haskell-language-server exe on the path.

[mrcjkb]

Hi. Thanks for the suggestion.
I'll add that to the upcoming 2.0.0 release.