Adding purescript-language-server to tools

[andys8]

Minor change: purescript-language-server also supports suggestions

[thomashoneyman]

I'm not able to merge this, but 👍

[thomashoneyman]

On second thought -- #347 updates the editor and tooling support section in the documentation and includes the language server. Does it make sense for there to be two documentation sections? Isn't this content already covered there?

I might be more in support of removing this documentation altogether.