This implements mapping of definitions in stubs to definitions in the "real" implementation using the approach described in https://github.com/astral-sh/ty/issues/788#issuecomment-3097000287 I've tested this with goto-definition in vscode with code that uses `colorama` and `types-colorama`. Notably this implementation does not add support for stub-mapping stdlib modules, which can be done as an essentially orthogonal followup in the implementation of `resolve_real_module`. Part of https://github.com/astral-sh/ty/issues/788