Provide a way to unregister a tag

[kolokolit]

Looking through the code, I’ve noticed that there’s a way to unregister a filter, but there’s no way to unregister a tag. Is it possible to add one?

Use case: I want to add a tag for adding YouTube videos in my theme, but don’t want to use more obscure name just because there’s a default tag (youtube) in place. I would’ve preferred to have a way to unregister default tag and add my own in its place.

[SukkaW]

Should be fixed in #4046