R1:a6fd8f04792d

When performing complex edits, pause sub-editors before they publish to propagate "Must Encrypt" and other state

Summary:
See PHI1134. Previously, see T13082 and D19969 for some sort-of-related stuff.

Currently, edits work roughly like this:

- Suppose we're editing object X, and we're also going to edit some other object, Y, because X mentioned Y or the edit is making X a child or parent of Y, or unblocking Y.
- Do the actual edit to X, including inverse edits ("alice mentioned Y on X.", "alice…