GitHub supported special markdown syntax for emphasising blocks for some
time. This was however a beta feature, and still is, so it's subject to
changes.
Recently such a change happened: The syntax is different now.
See https://github.com/orgs/community/discussions/16925 for more
information
Section in the manual have been preserved with a simple redirect to
GitHub, the proper anchors should be filled out in a future commit once
the new section names are decided.
