Let's try adressing the questions first and then some more general stuff:
Why did I not get a notification that my question received and edit?
This MSE post suggests that edits need to meet certain criteria to trigger a notification. You should have received a notification for the change in title.
Although no constexpr tag exist, this is the single most relevant one, yet a moderator changed this and undid my rollback (twice). How to proceed with getting the tags in order
The constexpr tag has been synonymized with the constants tag. If you disagree with that, I highly suggest splitting that out into a separate meta question.
For some reason or other you kept rolling back to a revision with a tag named c++2a. Which C++ standard is 2A?
Additionally Revisions 4 - 7 suggest that you're not really familiar with how rollbacks work. Seeing without context a rollback to revisions 2, 3, 2, 1 (in that order), I'd have to assume that you actually wanted to change something based on revision 3, and roll back to that first.
The tags of the question are at the time of writing:
c++ sudoku constants c++20
That seems just fine to me.
Why can't I report incorrect edits?
Because you can unilaterally roll them back. What are you trying to achieve by reporting them?
Do you agree that sudoku should not be in as a tag, nor in the title?
Huh? The problem domain of your question is a sudoku. While your question is not formulated around that and you're asking about a different aspect of the code, that doesn't mean it's irrelevant.
Tags are not there for you to like them, they're there to help categorize a question without needing to open and read it. If a tag helps categorize a question better than no tag, that tag should be added. If you don't have tags left to spare, you should trade off the usefulness of categorizations against one another.
In summary: No, I do not agree it shouldn't be there. (also it is not in the title...)
As C++ is evolving rapidly, I was experimenting with one of its features: constexpr.
the Cppreference site on constexpr suggests that constexpr has been available since C++11. The semantics changed a little through the standards.
Even worse, it was replaced by the tags constants, which is as relevant as a tag called classes or object oriented programming.
"It means constant expression". At least according to Microsoft's C++ Docs. Oh and from earlier linked cppreference:
"specified that the value of a variable or function can appear in constant expressions".
I'd say constants is an appropriate enough synonym for now. As noted above: Concerns about the tag synonymization should be handled in a dedicated meta post to elicit a community-consensus.
