Need to update with SIV support in mind

SIV was introduced after docgen, so we need to account now for the project path when generating import paths.

I'm too busy and wont have time for this, but if someone wants to tackle it, im happy to review a PR

Start by tracing where docgen generates import paths and identify how the project path is currently determined. Confirm the expected behavior for projects using SIV, then add coverage for that case and verify the generated import paths.

Written by the indexing model from the issue text.