Support omnisharp-vim features

[aymanbagabas]

omnisharp-vim appears to offer a lot of LSP features including completion, codeactions, diagnostics, symbols, etc. Could be used here too.

[yatli]

completion, diagnostics, symbols are already supported.
as for CodeActions -- it depends on when Omnisharp decides to bring LSP-compatible code actions into play. Currently, omnisharp seems to support that with custom messages.

[razzmatazz]

BTW, code actions should be working once we have this PR merged:

• LSP: wire up handler for codeAction OmniSharp/omnisharp-roslyn#1795

[artkpv]

I've tried this coc-omnisharp. It now lacks enhanced code highlighting (works in omnisharp-vim), tab completion is collapses methods with similar signature, documentation is shown with escape chars (''). So it looks like this coc plugin is still inferior to omnisharp-vim.

[Tantol]

I've tried this coc-omnisharp. It now lacks enhanced code highlighting (works in omnisharp-vim), tab completion is collapses methods with similar signature, documentation is shown with escape chars (''). So it looks like this coc plugin is still inferior to omnisharp-vim.

Same for me. Fact that documentation is shown with escape chars triggers me so much that I can not use this plugin 😄

[yatli]

@artkpv @Tantol thanks. I'll make a new work item to reformat the incoming doc string..