Bools and returns super-pr (#53221)

Replaces like 70-80% of 0 and such, as a side effect cleaned up a bunch of returns
Edit: Most left out ones are in mecha which should be done in mecha refactor already
Oh my look how clean it is

Co-authored-by: TiviPlus <TiviPlus>
Co-authored-by: Couls <coul422@gmail.com>

code/modules/procedural_mapping/mapGeneratorModule.dm

@@ -105,17 +105,16 @@
 
 //Checks and Rejects dense turfs
 /datum/map_generator_module/proc/checkPlaceAtom(turf/T)
-	. = 1
 	if(!T)
-		return 0
+		return FALSE
 	if(T.density)
-		. = 0
+		return FALSE
 	for(var/atom/A in T)
 		if(A.density)
-			. = 0
-			break
+			return FALSE
 	if(!allowAtomsOnSpace && (isspaceturf(T)))
-		. = 0
+		return FALSE
+	return TRUE
 
 
 ///////////////////////////////////////////////////////////