Changelog with both rst, github, and specific message output #10657
Description
Current problem
When releasing we must remove a lot of rst links and in order to use the text in github PR and github release note. If we want to use ``:ref`invalid-name``` it's also going to be necessary to generate the output automatically.
It would also be nice to have a changelog specific to a message in a message documentation.
Desired solution
For the generation tbump/towncrier need to include a new script for each use. We possibly need more semantic understanding in the way we generate the changelog (i.e. this change is linked to this message, or this extension, this checker, this option...)
For the changelog linked to a specific message page. We definitely need semantic and probably a sphinx extension.
Additional context
Noticed during 4.0.0 release because there was a lot of manual work as the changelog was huge. Specific message changelog suggested in #10649 (comment)