fix formatting (the linter did not find an elegant solution this time)

modified comments pertaining to function arguments to not be reliant on a particular formatting (// to /* */)

I'm not blocking on this, but FYI there are a bunch of same line comments in validation_chainstate_tests.cpp

fix -Werror=ignored-qualifiers

fix accidental revert of core#19132

rebase

In D9253#210657, @majcosta wrote:

now you reverted PR19132's changes completely

now you reverted PR19132's changes completely

remove unnecessary line added accidentaly when fixing conflict

remove line accidentaly added while fixing a conflict

updated backporting.md

fixing docs

added test cases and removed test cases that no longer apply (the number of digits in PRs are no longer in the code)

making the tests happy

In D9257#210616, @PiRK wrote:

Ok wigh core-gui. But something need to be done about the automatic " PRxxxx to URL" conversion.

Ok wigh core-gui. But something need to be done about the automatic " PRxxxx to URL" conversion.

Implementing suggested changes

yea this ain't worth it

we need to come up with a standard notation to ease automation of tagging the done backports in the bitcoin-core/gui repo, what about using Backport of core-gui PRxxxxxx?

rebase

squasjed with D9253

squash D9253 and D9256