Update our RTD redirects to use `latest` for dev, `stable` for errors
# It is related to Read the Docs, but is not a file processed by the platform.
/dev/news-entry-failure: >-
- https://pip.pypa.io/en/stable/development/contributing/#news-entries
+ https://pip.pypa.io/en/latest/development/contributing/#news-entries
/errors/resolution-impossible: >-
- https://pip.pypa.io/en/latest/topics/dependency-resolution/#dealing-with-dependency-conflicts
+ https://pip.pypa.io/en/stable/topics/dependency-resolution/#dealing-with-dependency-conflicts
/surveys/backtracking: >-
https://forms.gle/LkZP95S4CfqBAU1N6
/warnings/backtracking: >-
