Refactor move classes to implement respective interfaces for better structure

Plugins/PkmnLib.Plugin.Gen7/Scripts/Moves/Assist.cs

@@ -14,10 +14,10 @@ namespace PkmnLib.Plugin.Gen7.Scripts.Moves;
 /// If the other Pokémon in the user's party do not know any eligible moves, Assist fails. 
 /// </remarks>
 [Script(ScriptCategory.Move, "assist")]
-public class Assist : Script
+public class Assist : Script, IScriptChangeMove
 {
     /// <inheritdoc />
-    public override void ChangeMove(IMoveChoice choice, ref StringKey moveName)
+    public void ChangeMove(IMoveChoice choice, ref StringKey moveName)
     {
         var user = choice.User;
         if (user.BattleData == null)