Allow posters to revert a post / access raw previous data

Bumping this because

  1. People could in theory just edit a post back if they had the old raw data on hand, so this is exclusively a QoL feature to allow them to go back to edits they no longer have the raw data for

  2. Mods already have this capability, so it surely already exists, and should not take much work to extend it to the original author of a post

  3. Based on the above two points I can think of no reason it shouldn’t be enabled, as it seems well worth the effort of merely extending permission of this feature to the author of a post