Pattern overrides, and the synced pattern that was almost right

A synced pattern used on forty pages where the layout should be shared and the text should not, which had meant an unsynced pattern and forty divergent copies.

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Marking specific blocks as overridable is the missing middle between synced and unsynced, and it is the thing that makes a synced pattern usable for a campaign layout. The constraint is that only some blocks support it — headings, paragraphs, images and buttons — so a pattern whose variable part is a group still has to be unsynced.