Being drunk or having a broken arm hurts accuracy with ranged weapons. Also cleans up a fair bit of hand handling to be more readable (#87904)

## About The Pull Request

1. Having a broken arm will affect your accuracy when firing a weapon
with that arm, even potentially causing damage to you if it's a weapon
with recoil. This effect is not applied under the effects of a
painkiller.

2. The sister effect of this (punching someone with a broken arm) now
also has an interact with painkillers (it can no longer block your
attack).

3. Being drunk heavily affects ranged weapon accuracy, unless you're the
bartender

4. A lot of hand handling cleanup, using new macros to make it a lot
more readable at a glance

## Why It's Good For The Game

We have this system for modifying firearm accuracy but we don't really
use it commonly, and I feel like it slots in well with a lot of places

For broken arms, it adds some more depth to the wound system, in the
same way that trying to punch someone with a broken arm causes pain. (I
actually want to expand this to melee weapon accuracy and attacking with
melee weapons in general, but that's for a later time)

For drunkenness, it just adds to the drunk shenanigans. It also slightly
reduces the effectiveness of drinks as combat healing chemicals, such as
quadsec - makes it a bit more of a trade off.

## Changelog

🆑 Melbert
balance: Having a broken arm affects your accuracy with ranged weapons
fired with that arm. Utilizing a painkiller will nullify this effect,
however.
balance: Painkillers will prevent your punches from being cancelled due
to having a broken arm. You'll still take damage, though.
balance: Being drunk now affects your accuracy with ranged weapon. The
bartender is immune to this effect via their skillchip.
code: A lot of code involving left and right hand handling has been
cleaned up, easier to read. Report any oddities, like left and rights
being flipped
/🆑

code/datums/components/basic_inhands.dm

@@ -39,7 +39,7 @@
 	SIGNAL_HANDLER
 	var/list/held_overlays = list()
 	for(var/obj/item/held in holding_mob.held_items)
-		var/is_right = holding_mob.get_held_index_of_item(held) % 2 == 0
+		var/is_right = IS_RIGHT_INDEX(holding_mob.get_held_index_of_item(held))
 		var/icon_file = is_right ? held.righthand_file : held.lefthand_file
 		var/mutable_appearance/held_overlay = held.build_worn_icon(default_layer = HANDS_LAYER, default_icon_file = icon_file, isinhands = TRUE)
 		held_overlay.pixel_y += y_offset