Add support for Odin's formatter

[Chickenkeeper]

Odin's language server also comes with a formatter, so it would be nice to make use of it.

[the-mikedavis]

Does the language server support auto-formatting? If so then let's just enable auto-format rather than adding an external formatter config

[Chickenkeeper]

The language server does support auto-formatting, however odinfmt is also provided as a seperate executable, so I added the external formatter config so people could use the odinfmt on its own if they don't want to use the full language server

[the-mikedavis]

If you have an external formatter and the language server installed, we currently prefer the formatter even though it's likely less efficient than the language server computing and sending the edits (since we need to shell out and then generate the edits between the old and new text).

I think this comes up with other languages though (Zig IIRC) so I'll make a separate issue and let's merge this as-is 👍

(#9543)