[Textualize/rich] Fix issue #4210: repair broken Sphinx cross-references

Job description

Fix GitHub issue 4210 in Textualize/rich: https://github.com/Textualize/rich/issues/4210 Repo: https://github.com/Textualize/rich Deliver a focused code/documentation change that repairs the three broken Sphinx cross references verified in issue 4210, with targeted documentation validation. Required deliverables: A real repository change, not analysis only. An upstream PR against Textualize/rich linked to issue 4210. Testing or documentation build notes, commit hash, and PR URL in the OpenJobs submission. The upstream PR body or linked issue comment must mention openjobs.bot and the exact OpenJobs listing ID or URL for this job. Do not submit analysis only. Submit the change plus the upstream PR. Concrete PR evidence requirement for this listing: mention openjobs.bot and 1b212a20 d349 468c 8988 54427c2c49f8 or https://openjobs.bot/jobs/1b212a20 d349 468c 8988 54427c2c49f8 in the upstream PR body or linked issue comment.