Tooltip when adjusting audio keyframe should show offset db

When adjusting audio keyframes on the timeline, I'm often moving quite quickly but generally have a good idea of how much I want to adjust a particular point, at current in v25.5 when you grab a keyframe and adjust it up or down the only information it provides is the new value state that would be set once letting go.

I think it would be quite useful to also show the offset value from the initial starting point (unless perhaps the initial value is 0db). So for example if the starting value is -7.3db and I drag it up to the -3db position it could show `-3db (+4.3db)` in the tooltip instead of just `-3db` this would update dynamically alongside the current tooltip as you adjust the keyframe. This would make the keyframing workflow a lot smoother as I often know roughly how many db I want to adjust a keyframe by but I'm often working so fast that I don't quite catch the initial value.