Rename all files in data/pokedex/entries/

Some people suggested this would be a good idea, and make management of
the files easier. I'm inclined to agree.

data/pokedex/entries/houndoom.asm

@@ -0,0 +1,10 @@
+; HoundoomPokedexEntry: ; 0x1d0f66
+	db "DARK@" ; species name
+	dw 407, 770 ; height, weight
+
+	db   "The pungent-"
+	next "smelling flame"
+	next "that shoots from"
+	page "its mouth results"
+	next "from toxins burn-"
+	next "ing in its body.@"