Move category membership RC updates to CategoryMembershipChangeJob
* Recursive link updates no longer mention an category changes.
It's hard to avoid either duplicate mentioning of changes or
confusing explicit and automatic category changes.
* LinksUpdate no longer handles this logic, but rather WikiPage
decides to spawn this update when needed in doEditUpdates().
* Fix race conditions with calculating category deltas. Do not
rely on the link tables for the read used to determine these
writes, as they may be out-of-date due to slave lag. Using the
master would still not be good enough since that would assume
FIFO and serialized job execution, which is not garaunteed.
Use the parser output of the relevant revisions to determine
the RC rows. If 3 users quickly edit a page's categories, the
old way could misattribute who actually changed what.
* Make sure RC rows are inserted in an order that matches that
of the corresponding revisions.
* Better avoid mentioning time-based (parser functions) category
changes so they don't get attributed to the next editor.
* Also wait for slaves between RC row insertions if there where
many category changes (it theory it could well over 10K rows).
* Using a separate job better separates concerns as LinksUpdate
should not have to care about recent changes updates.
* Added more docs to $wgRCWatchCategoryMembership.
Bug: T95501
Change-Id: I5863e7d7483a4fd1fa633597af66a0088ace4c68