feature: API checks: diff each sequence/mapping value instead of the whole

[pawamoy]

Is your feature request related to a problem? Please describe.

Griffe warns about changed values for attributes, but these are often false positives.

Describe the solution you'd like

Instead of diff a whole dictionary, we should check each one of its key/value pairs. Key removed? Breaking change. Value changed? Breaking change. Added key? Not a breaking change.

Same for lists/tuples, but check ordering too. For sets, only check that nothing was removed.

Describe alternatives you've considered

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Additional context

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