Feature request: support code formatting using erlfmt

[eproxus]

One noticeable thing missing from ELP, when switching from erlang-ls, is code formatting. It would be nice if ELP could format code using erlfmt (reading any relevant configuration from rebar.config etc.).

[robertoaloi]

@eproxus It's an option. Currently we have this feature internally via a direct VS Code integration. I wonder if, for the time being, we could at least port it to the OSS version of the extension + Emacs. And, medium-term, have formatting going through LSP.

@michalmuskala is there any special reason why erlfmt is not integrated via the protocol?

[eproxus]

Just FYI I'm using Zed, so anything built-in into the LSP would be the easiest.

[michalmuskala]

@robertoaloi What do you mean by the protocol?

[alanz]

@michalmuskala see https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#textDocument_formatting

[michalmuskala]

Ah, I think this was primarily to avoid direct dependency from ELP on erlfmt, but this might be less of a concern now that erlfmt isn't evolving that much