[Character Sheet] Merge Identical Hit Dice

Players get one hit dice per level in each of their classes. For single-class characters this is nice and easy, and you get a single pool of dice to roll equal to your character level.

For multi-classing however the hit dice are separated into different pools for each class you belong to. This makes sense if you multi-class and your classes don't share the same die type, but it just makes the UI more cluttered when multi-classing into classes with the same die.

For example, with my current main character I'm a fourth level Bard (d8), and and a 1st level Rogue (also d8), this gives me two pools of d8's, one with four dice and one with one dice, but they're both otherwise exactly the same.

I'd like to propose that instead of showing these separately, that they instead be grouped together by die type, and highlighted in some other way, for example colour. So I might have four blue HP die (Bard), and one red HP die (Rogue) so I can still mark them off separately in the event that some affect applies only to a single classes' die (not that I'm aware of any).