minor code cleanup + fixes plasma fixation

code/__DEFINES/atmospherics.dm

@@ -1,8 +1,5 @@
 //LISTMOS
 //indices of values in gas lists.
-#define MOLES			1
-#define ARCHIVE			2
-#define GAS_META		3
 #define META_GAS_SPECIFIC_HEAT	1
 #define META_GAS_NAME			2
 #define META_GAS_MOLES_VISIBLE	3
@@ -243,7 +240,7 @@
 //HELPERS
 #define THERMAL_ENERGY(gas) (gas.temperature * gas.heat_capacity())
 
-#define ADD_GAS(gas_id, out_list) out_list[gas_id] = 0;
+#define ADD_GAS(gas_id, out_list) out_list[gas_id] = 0
 
 #define ASSERT_GAS(gas_id, gas_mixture) if (!gas_mixture.gases[gas_id]) { ADD_GAS(gas_id, gas_mixture.gases) };
 

code/datums/diseases/advance/symptoms/heal.dm

@@ -371,7 +371,7 @@
 	if(M.loc)
 		environment = M.loc.return_air()
 	if(environment)
-		plasmamount = environment.gases["plasma"]
+		plasmamount = environment.gases[/datum/gas/plasma]
 		if(plasmamount && plasmamount > GLOB.meta_gas_info[/datum/gas/plasma][META_GAS_MOLES_VISIBLE]) //if there's enough plasma in the air to see
 			. += power * 0.5
 	if(M.reagents.has_reagent("plasma"))

code/modules/atmospherics/gasmixtures/gas_mixture.dm

@@ -62,7 +62,7 @@ GLOBAL_LIST_INIT(meta_gas_info, meta_gas_list()) //see ATMOSPHERICS/gas_types.dm
 
 	//PV = nRT
 
-/datum/gas_mixture/proc/heat_capacity(data = MOLES) //joules per kelvin
+/datum/gas_mixture/proc/heat_capacity() //joules per kelvin
 	var/list/cached_gases = gases
 	. = 0
 	for(var/id in cached_gases)