Previously, some links to specific sections of `CONTRIBUTING.md` were
using hashes automatically generated by GitHub based on the section
headings. This resulted in less readable hashes which were directly tied
to the heading text and thus less robust (i.e. more likely to break if
the heading was re-worded in the future).
This commit switches such links to use the dedicated anchors, which are
more succinct/readable and more stable.
PR Close#41250
George Kalpakas
David Shevitz