Some misc explicit interfaces

Just a by-product from a previous commit, not meant to do anything specific other than bringing us a tiny step closer to requiring explicit implementations for these interfaces too, at some point.

OpenRA.Mods.Common/Traits/AttackMove.cs

@@ -78,7 +78,7 @@ namespace OpenRA.Mods.Common.Traits
 				assaultMoveToken = conditionManager.RevokeCondition(self, assaultMoveToken);
 		}
 
-		public string VoicePhraseForOrder(Actor self, Order order)
+		string IOrderVoice.VoicePhraseForOrder(Actor self, Order order)
 		{
 			if (order.OrderString == "AttackMove" || order.OrderString == "AssaultMove")
 				return info.Voice;