LSP code action to create unknown module

[tarkah]

It'd be nice if there was a way to create unknown modules for the current package via LSP code actions. Since gleam doesn't have explicitly defined module declarations (like in Rust with mod foo.rs), it'd make sense for this code action to be available on the import declaration, along with its corresponding "unkown module" diagnostic

An initial implementation has been drafted here: #4888

Open questions:

• Should we allow creating modules anywhere in the current project or only direct submodules of the current module?

[GearsDatapacks]

As I mentioned in the PR, my vote is for allowing it on any module, as I feel that makes the most sense. Modules don't always import submodules so I think it would be useful to support that

[tarkah]

Agreed, I've thought about it more and with the module system in gleam I think it makes a lot of sense.

I'll update the draft to include this change.

[tarkah]

I've updated the draft with this change. Not only does it simplify the implementation (we can just append origin path + module name + .gleam), but it fundamentally makes sense w/ gleams module system. Thanks for the feedback!

@GearsDatapacks let me know if we're ready to move #4888 out of draft or if we need to solicit any more consideration.

[GearsDatapacks]

I think undrafting the PR is fine at this stage. If anyone has more thoughts about this they can comment here or on the PR

[lpil]

Sounds useful!