Send Announcement when method is deleted so that code queries are updated and remove it

[botwhytho]

Code query views seem to dynamically update, for example if you add a method on a new class/instance, in another tab the result of implementors updates automatically which is GREAT!!! Hoping that view can get updated with the opposite, if you remove that method, that view should subscribe to such a system announcement and get updated as well.

[girba]

This is a little tricky.

When we have a filter, and start reworking a method in that view, we typically do not want it to be removed the first time we save. That is why we only add at this moment.