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/electabuzz.asm

@@ -0,0 +1,10 @@
+; ElectabuzzPokedexEntry: ; 0x1b992a
+	db "ELECTRIC@" ; species name
+	dw 307, 660 ; height, weight
+
+	db   "When two"
+	next "ELECTABUZZ touch,"
+	next "they control the"
+	page "electric currents"
+	next "to communicate"
+	next "their feelings.@"