`<some_id>.keyframe_insert()` now sends a notifier that animation data
was changed, so that animation-related editors can properly refresh.
Since this function is quite high-level (if necessary it creates the
Action and FCurves), I thought this would be a suitable location for the
notifier. If high keyframing speed is required, it is still recommended
to use `FCurveKeyframePoints.insert(options={'FAST'})` instead.
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