Watch for post slug changes before saving them

[ramsesdelr]

This watches for slug changes on posts that have children posts. If a child post is found on this condition, it's saved inside a transient to be synced after the post is updated.

[tw2113]

@ramsesdelr To make sure I'm following correctly:

1. upon post type post update, it checks for slug change. If yes, it checks for children and temp stores those.
2. Once post saved, it enters the Algolia sync step, and updates not only the parent, but also the temp stored children.

Basically everything should be known and calculated by the time any syncing is done with Algolia?

[ramsesdelr]

@tw2113 That's correct, everything should be in place before syncing with Algolia.