Deprecate Procedural hook implementations

I had assumed we'd trigger E_USER_DEPRECATED in hook discovery, once per module when we find a procedural hook, should be cheaper?

Hook collector picks up all functions that start with module name.

It looks like the patch only triggers a deprecation for hooks called by ModuleHandler::invoke() and not those called byModuleHandler::invokeAllWith().

Yeah this isn't the approach we would take at all. Let me postpone it, not sure on what though.