Fixes newfood reagent transfer and food trash' to_chat (#55150)

Co-authored-by: Jared-Fogle <35135081+Jared-Fogle@users.noreply.github.com>

code/modules/reagents/chemistry/holder.dm

@@ -324,6 +324,22 @@
 	src.handle_reactions()
 	return amount
 
+///Multiplies the reagents inside this holder by a specific amount
+/datum/reagents/proc/multiply_reagents(multiplier=1)
+	var/list/cached_reagents = reagent_list
+	if(!total_volume)
+		return
+	var/change = (multiplier - 1) //Get the % change
+	for(var/reagent in cached_reagents)
+		var/datum/reagent/T = reagent
+		if(change > 0)
+			add_reagent(T.type, T.volume * change)
+		else
+			remove_reagent(T.type, abs(T.volume * change)) //absolute value to prevent a double negative situation (removing -50% would be adding 50%)
+
+	update_total()
+	handle_reactions()
+
 /// Transfer a specific reagent id to the target object
 /datum/reagents/proc/trans_id_to(obj/target, reagent, amount=1, preserve_data=1)//Not sure why this proc didn't exist before. It does now! /N
 	var/list/cached_reagents = reagent_list