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/sudowoodo.asm

@@ -0,0 +1,10 @@
+; SudowoodoPokedexEntry: ; 0x1cd7d9
+	db "IMITATION@" ; species name
+	dw 311, 840 ; height, weight
+
+	db   "If a tree branch"
+	next "shakes when there"
+	next "is no wind, it's a"
+	page "SUDOWOODO, not a"
+	next "tree. It hides"
+	next "from the rain.@"