What is the future of rdrr?

Just an issue to note that we use `rdrr` links for our cheatsheets, but recently `rdrr` has been down quite a bit! If this level of downtime continues, we _might_ rethink links.

Review the cheatsheets that currently use rdrr links and confirm which links are affected by the reported downtime. The issue is complete only after a decision is recorded on whether those links should remain or be reconsidered; no file or test is identified.

Written by the indexing model from the issue text.