Ability to discard draft changes, atomically

[AugustMiller]

When working on a draft (provisional or saved), Craft will periodically merge in changes from the canonical element—at least for fields and attributes that weren't modified in the draft itself.

In situations where a correction is made as part of an unrelated draft (perhaps bad form, but who can resist!), but also updated on the canonical element, applying the draft will overwrite that correction, perhaps reverting it.

If we could "discard" changes on a field-by-field basis, it would be possible to manually resolve this kind of collision… sort of like merge conflicts, in git ("keep my change" vs. "keep their change"). Perhaps this begins with an alternate status indicator (like a yellow stripe) for fields and attributes that have been modified in both locations?