Fixing reload_furniture to allow reloading with ammo other than the default

[katemonster33]

Summary

Bugfixes "Fixes issue where loading a forge with coal does not work"

Purpose of change

Fixes: #68371

Describe the solution

reload_furniture in iexamine.cpp was modified to look at multiple ammo types for a single object. this involves taking into account situations where, in the case of the forge, it could be 40% full of charcoal, and the user wants to put coal in, we need to calculate how much coal they can load it with.

Describe alternatives you've considered

Testing

loaded save linked in issue, deposited coal into forge, see that the game prompts me on subsequent calls to reload_furniture to unload said coal

Additional context

[RenechCDDA]

Still looking for this to restrict loading to a single ammotype at a time, don't know if you can easily merge Nornagon's commits from #72743

[katemonster33]

Still looking for this to restrict loading to a single ammotype at a time, don't know if you can easily merge Nornagon's commits from #72743

working on it, there's a lot of moving parts with nornagon's PR and I'm trying to figure out what parts of mine can be kept

[katemonster33]

also i rebased with nornagon's change. since the code changes seemed very different i just took the JSON change. hope that's ok @nornagon

[katemonster33]

sorry, triple-post... furniture should only take single ammo type now

[RenechCDDA]

Looks good now, thanks for the hard work!