Clean up mauville_old_man, drop ScrSpecial prefix

include/wild_encounter.h

@@ -33,7 +33,6 @@ extern const struct WildPokemonHeader gWildMonHeaders[];
 
 void DisableWildEncounters(bool8 disabled);
 bool8 StandardWildEncounter(u16 currMetaTileBehavior, u16 previousMetaTileBehavior);
-void ScrSpecial_RockSmashWildEncounter(void);
 bool8 SweetScentWildEncounter(void);
 bool8 DoesCurrentMapHaveFishingMons(void);
 void FishingWildEncounter(u8 rod);