Adapt LspDiagnostics* highlight groups to latest neovim upstream changes (fixes #147)

[ybc37]

Hey there!

I adapted the highlight groups based on:

• :help lsp-highlight-diagnostics
• Info in diagnostic-nvim: [IMPORTANT] Deprecation & Transition Strategy nvim-lua/diagnostic-nvim#73
• The commit in neovim (relevant changes)

I set LspDiagnosticsDefault* and removed virtual text and floating highlight groups, because they link to default, AFAIU. Fixes #147.

Would be great if someone could review/test :) Thanks!

[rbong]

Can you keep the old highlight groups for now and add the new ones, and add a comment indicating that? I'd like to not break older versions of nvim for now. Thank you!

[ybc37]

Thanks for the fast feedback :)

IMHO it's not worth to keep the previous highlight groups for compatibility, because neovims built-in LSP wasn't released yet in an official version. It only concerns people following head.

But if you still prefer to keep them I'll change it, of course! (I'm just afraid I can't do it before Sunday.)

[rbong]

Ah okay, I didn't know that. That's fine then.