Support Autocompletions for Custom Local Namespaces Discovery

[jassielof]

Motivation

Currently, Tinymist (VS Code, pre-release version) can only monitor for @local/ namespaces to import, while in fact, Typst support custom namespaces, "local" just being a default convention.

Description

Basically, just the ability for Tinymist to support monitoring (IntelliSense/completions) for other custom namespaces, other than just "local", for example: github, gitlab, etc.

More Examples/Questions

On Linux, at least, if we add more namespaces to ~/.local/share/typst/packages/{local, github, gitlab}/<some packaged copied from the preview one>, only the "local" namespace is autocompleted.

[StijnNowee]

Would greatly appreciate this addition. I am struggling with the same issue.