I'm a big fan of how Discourse handles it. If the post edit is larger than a threshold (iirc damerau-levenshtein distance) and after a short period of it's creation, the diff is saved. Clicking the edit pencil on a post let's you view all the revisions of a post
Moderators have the ability to "squash" the edits down and hide them, in the event that they're removing pii or something like that
Amusingly, jedberg wrote the distance checking function into reddit ages ago, to make the edited mark less sensitive to minor typo corrections, but the patch seemingly got removed a short while after it was added. For a brief period, you could edit punctuation and small spelling mistakes and not get the edit badge