compiler considers code in modules/packages to be standard modules

[mppf]

Currently, the compiler applies MOD_STANDARD to code parsed from modules/packages. This means that this code isn't being checked with unstable warnings and a variety of other checks. At the same time, since modules/packages can be viewed as a place for code that could be mason packages but that is bundled with the release, it's more appropriate to label it with MOD_USER than MOD_STANDARD.

This issue serves as a place to track the TODO of resolving this issue and to discuss.

[lydia-duncan]

Note that making package module code "user" may also impact standard library code as well - e.g. the Sort module is unstable, so changes to its behavior could impact places that use the Sort module (though obviously, it'd be nice if we could get our standard libraries to only rely on standard library code, either by removing references to package modules or stabilizing the module being used - if you find cases like that, feel free to ping me and I'll prioritize having someone on the stabilization team work on it)