Replace usages of Title::isWatchable() with WatchlistManager::isWatchable() and hard deprecate Title::isWatchable().
Wikimedia production extensions/skins:
- Flow
- MinervaNeue
Other extensions/skins:
- BlueSpiceSocialWatch
WatchAnalytics(filed an issue, but not a patch since the extension does not currently support MW 1.36+)
Core:
- Remove usages in core
- Hide deprecations in Title tests
- Hard deprecate Title::isWatchable()