change the way fail works

[cooper]

I'm thinking fail should not stop event propagation. The reason I made it do that is if subsequent callbacks depend on the one that failed, bad things might happen. But now I thought of something else that might be better. If a callback fails, cancel all subsequent callbacks which refer to the one that failed in an after priority hint.

[cooper]

This would eliminate ->error_continue. I would also have to make it so events yield an error only if the number of failures is equal to the number of functions called. This would also work if both are zero.

[cooper]

Currently an after hint does not stop the callback from executing if the referenced one is not executed. This would change that. There needs to then be a way to say "after X if applicable, but anytime otherwise" ... maybe after? 🤣

[cooper]

Also we can't just "cancel" the dependent callbacks. They would have to fail too. That way the overall event fails if the default callback fails and all other callbacks were dependent on it.

[cooper]

Also on X should probably implicitly mean on X after :default