Correct calculation of count_by_charge items where volume > 1

[mugling]

Closes #15331

[BevapDin]

What has the "Stack size" information to do with the volume? Isn't it supposed to show the stack size itself, as in "the number of charges per default stack"? If the calculation is the desired thing to show, the information should be renamed to something like "Charges per 1 volume" or so.

Also: type->volume can be 0, can't it? If so, std::min( type->volume, 1U ) can easily be 0 as well.

Edit: It currently crashes the game when looking at sugar beet seeds in the item wish menu. The seeds have stacks size 40, charges 4 (therefor counted by charges) and volume 0.

[mugling]

What has the "Stack size" information to do with the volume?

Normalized to show charges per unit volume which is what the player needs to know to determine how much an item's volume increases/decreases as the number of charges varies.

type->volume can be 0, can't it? If so, std::min( type->volume, 1U ) can easily be 0 as well.

Might be best to avoid showing that field at all for volume == 0 as it's not relevant if the item has no volume.

Edit: It currently crashes the game when looking at sugar beet seeds in the item wish menu. The seeds have stacks size 40, charges 4 (therefor counted by charges) and volume 0.

In the long term it might be best to avoid specifying volume 0 for AMMO and COMESTIBLE - in the above example seeds should have volume. That said, obviously we need to avoid the crash and I'll look into that.