language server support

I'd be curious if you've considered adding language server support? With syntax coloring and multi-line editing, the experience is already part way to an editor, it would be awesome to finish it out!

I'm imaging something like inshellisense for auto complete, plus it would probably be possible to add diagnostics.

If it were configurable by the end user, it would be really cool to allow the user to run multiple language servers at once so they could add things like snippets or code aware spell checking. I'm imaging something like Helix's ability to add any language server via languages.toml.

This would be really cool in nushell, but I'm admittedly hoping it trickles down to brush shell (which uses reedline) to use with bash.

The issue names no source files, tests, or entry points. Start by reviewing reedline's existing editor and completion behavior, then read the linked inshellisense and Helix languages.toml references; done would require an agreed design for configurable multiple language servers covering completion, diagnostics, snippets, and spell checking.