Add a way to add Custom CodeMirror support for languages

[NullVoxPopuli]

Is your feature request related to a problem?

I would like to add codemirror support for Ember's gjs and gts filetypes.

I already saw similar issues:

• https://github.com/stackblitz/tutorialkit/pull/212
• https://github.com/stackblitz/tutorialkit/pull/256
• https://github.com/stackblitz/tutorialkit/issues/357

but saw that an extensible API was not added, but Svelte support is now just built in to tutorial kit.

I already did the work to create codemirror plugins for https://share.glimdown.com/_uXZKpvFRx63MJp7lEhk6A, code here:

• https://github.com/NullVoxPopuli/limber/blob/main/packages/app-support/codemirror/preconfigured/index.ts#L63
  • packages:
    • codemirror-lang-glimmer (hbs)
    • codemirror-lang-glimmer-js (gjs)
    • for gts, I still need to finish making codemirror-lang-glimmer-ts

Describe the solution you'd like.

a way to pass a function or an array of mappings for filetypes -> plugins for codemirror to load

• the syntax plugin
• the array of support plugins (completions, etc)

Describe alternatives you've considered.

I could PR direct support for gjs/gts to tutorial kit

Additional context

<3