More abilities, refactor IPokemon.SetStatus to pass pokemon that caused the status change

Plugins/PkmnLib.Plugin.Gen7/Scripts/Abilities/SwiftSwim.cs

@@ -0,0 +1,19 @@
+namespace PkmnLib.Plugin.Gen7.Scripts.Abilities;
+
+/// <summary>
+/// Swift Swim is an ability that doubles the Pokémon's Speed in rain.
+///
+/// <see href="https://bulbapedia.bulbagarden.net/wiki/Swift_Swim_(Ability)">Bulbapedia - Swift Swim</see>
+/// </summary>
+[Script(ScriptCategory.Ability, "swift_swim")]
+public class SwiftSwim : Script
+{
+    /// <inheritdoc />
+    public override void ChangeSpeed(ITurnChoice choice, ref uint speed)
+    {
+        if (choice.User.BattleData?.Battle.WeatherName == ScriptUtils.ResolveName<Weather.Rain>())
+        {
+            speed = speed.MultiplyOrMax(2);
+        }
+    }
+}