feat: highlight / select symbol under cursor using LSP textDocument/documentHighlight

[lazytanuki]

Hi !

This PR implements the LSP textDocument/documentHighlight request. The command asks the LSP server for the ranges of references to current symbol, and select them (using multiple cursors).

I initially just wanted to have these symbols highlighted (like in nvim or vscode), but using multi-cursors is more convenient because the user can navigate between the references using ( and ), and also because it reuses already existing components :

I have set the Space + h (for highlight) mapping to use this.

Have a good day !

[lazytanuki]

Changes made, thanks for the review !

[sudormrfbin]

LGTM!

[joegm]

As for the keybind, wouldn't m-h be better than space-h? This feels like a "match" command.

[lazytanuki]

Now that you mention it, indeed it does look like a match command. I chose 'h' for highlight because the call to LSP is textDocument/documentHighlight, although maybe something else than 'h' would make more sense as well ?
What do others think ?

[joegm]

Maybe m-S for 'Symbol' ? Lowercase s is already used (although we could change that to w for 'wrap'..?).

[lazytanuki]

I don't think changing m-s would be such a good idea, it might already be muscle memory for current users. m-S could do it.

[archseer]

@the-mikedavis any opinions on keymaps here?

I initially just wanted to have these symbols highlighted (like in nvim or vscode), but using multi-cursors is more convenient because the user can navigate between the references using ( and )

I think this is a smart way of doing it, especially since it makes it easy to rename all occurrences (if the lsp doesn't support the rename code action)

[the-mikedavis]

I didn't mind space-h but I don't have any problems with mS either. My only hold-up with m is that it's usually used for matches and textobjects and I don't think this fits in perfectly with that. Given that hover and rename are already in space I think adding more is ok

[lazytanuki]

Okay, should we go back to space-h then ?

[the-mikedavis]

Yeah let's go for space-h for now, we can always revisit the binding later

[lazytanuki]

Alright, done !

[the-mikedavis]

This is awesome, thanks for working on it!

[archseer]

Great work!