Kills screen-wide EMPs (#11375)

* Kills screen-wide EMPs

This makes a small line change to make the EMP reaction's size be determined logarithmically, rather than linearly. That meaning, there's diminishing returns on EMPs. As a consequence, there's not TOO much reason to try to make a very big EMP, like with maxcaps (before toxins became research, anyway), though I'm sure some of you, who like to get the largest numbers on things possible, can still reach some ungodly numbers with payloads. You're welcome to reach for new heights, but you shouldn't be able to lolEMP the entire station.

* EMP shrinking 2

code/modules/reagents/chemistry/recipes/pyrotechnics.dm

@@ -114,9 +114,12 @@
 
 /datum/chemical_reaction/emp_pulse/on_reaction(datum/reagents/holder, multiplier)
 	var/location = get_turf(holder.my_atom)
-	// 100 multiplier = 4 heavy range & 7 light range. A few tiles smaller than traitor EMP grandes.
-	// 200 multiplier = 8 heavy range & 14 light range. 4 tiles larger than traitor EMP grenades.
-	empulse(location, round(multiplier / 12), round(multiplier / 7), 1)
+	// 50 multiplier = 4 heavy range & 7 light range. A few tiles smaller than traitor EMP grandes.
+	// 100 multiplier = 5 heavy range & 10 light range.
+	// 200 multiplier = 7 heavy range & 14 light range. 4 tiles larger than traitor EMP grenades.
+	// 300 multiplier = 8 heavy range & 17 light range. Still rather significant, considering that you can get dozens of bluespace beakers 30 minutes in with a competent crew.
+	// 900 multiplier = 12 heavy range & 30 light range. Still less than 300 before this commit.
+	empulse(location, round(multiplier ** (3/8)), round(multiplier ** (1/2)), 1)
 	holder.clear_reagents()