Clean up comments

Base data: types uniquely lacked a comment; items on one line; distinguish unknowns
Dex entries: don't imply that pointers don't exist

data/pokemon/dex_entries/gengar.asm

@@ -1,10 +1,10 @@
-; GengarPokedexEntry: ; 0x1b8c25
 	db "SHADOW@" ; species name
 	dw 411, 890 ; height, weight
 
 	db   "Hiding in people's"
 	next "shadows at night,"
 	next "it absorbs their"
+
 	page "heat. The chill it"
 	next "causes makes the"
 	next "victims shake.@"