Check if target of attack is a valid target for that attack.

Signed-off-by: Deukhoofd <Deukhoofd@gmail.com>

src/Battling/Flow/ResolveTarget.hpp

@@ -12,6 +12,9 @@ namespace CreatureLib::Battling {
     public:
         static TargetList ResolveTargets(const CreatureIndex& index, CreatureLib::Library::AttackTarget target,
                                          const ArbUt::BorrowedPtr<Battle>& battle);
+
+        static bool IsValidTarget(const CreatureIndex& index, CreatureLib::Library::AttackTarget target,
+                                  const ArbUt::BorrowedPtr<Creature>& user);
     };
 }