feat: 添加扩展获取命令发送者方法

Signed-off-by: 502647092 <admin@yumc.pw>

src/main/java/pw/yumc/YumCore/commands/CommandArgument.java

@@ -50,4 +50,11 @@ public class CommandArgument {
         return sender;
     }
 
+    /**
+     * @return 命令发送者(自动转换)
+     */
+    @SuppressWarnings("unchecked")
+    public <CS> CS getSenderEx() {
+        return (CS) sender;
+    }
 }