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/sandslash.asm

@@ -1,10 +1,10 @@
-; SandslashPokedexEntry: ; 0x1821e7
 	db "MOUSE@" ; species name
 	dw 303, 650 ; height, weight
 
 	db   "Adept at climbing"
 	next "trees, it rolls"
 	next "into a spiny ball,"
+
 	page "then attacks its"
 	next "enemies from"
 	next "above.@"