Moving to language server

[castwide]

The legacy web server (solargraph server) is liable to be deprecated in an upcoming version. Clients are recommended to switch to the language server if possible.

Discussion here: castwide/solargraph#50

[hackhowtofaq]

Thanks for the info. I ll try to find some spare time to refactor the plugin

[castwide]

Great, thanks. In the meantime, the current plugin should still work with gem versions < 0.21.0. (In one case that still used solargraph server, I had to revert back to gem 0.17.4.)

[kingdonb]

I found this second, wished it had been linked here: https://blog.schembri.me/post/solargraph-in-vim/