Better stop repeating UX

Currently it's not obvious how to stop a post repeating. It should be.

There are two ways to stop a post repeating currently:

1. Edit the original post and set it to not repeat.
2. Delete the next scheduled post so that the repeat cycle is broken.

1 should really be the only intentional way, but needs to be made more obvious as a users natural inclination is to edit the current post or the next scheduled post rather than the original.

2 is almost a bug as it's not clear that the users intention was that the repeating should be canceled just because they deleted the next scheduled post, maybe they just wanted to skip that week for example...

The issue does not name files or tests; start by reproducing both documented ways of stopping a repeating post in the WordPress plugin and tracing the related post-edit and scheduling flows. Done means the intentional cancellation path is obvious to users and deleting a scheduled post does not unexpectedly cancel future repeats, with the behavior covered by an appropriate test or documented verification.

Scritto dal modello di indicizzazione a partire dal testo della issue.