Support erb-formatter

[andyw8]

erb-fomatter seems to be a good modern choice for ERB formatting. It would be nice to have it supported by default by the Zed Ruby extension.

NOTE: The README includes instructions for Zed, but they need updated. I've opened a PR. ✅

[vitallium]

Yeah, totally agree here. Unfortunately, Zed does not currently support custom formatters defined by extensions. I wonder if we could start by adding documentation about using erb-formatter for ERB files:

"ERB": {
  "formatter": {
    "external": {
      "command": "erb-formatter",
      "arguments": ["--stdin-filename", "{buffer_path}"]
    }
  }
}

[andyw8]

For this kind of thing, I wonder if it's better to start adding the docs in the extension README rather than Zed's documentation. It would ease the burden on the Zed team needing to review such changes.

[joeldrapper]

A language server could do formatting though. Isn’t @marcoroth building one with Herb?

[marcoroth]

Yes, Herb is going to ship a formatter. Mostly likely as a standalone CLI and maybe as part of an integration with Ruby LSP.