Swift templates tweaks. (#13291)

Dropped optional semicolons.

packages/flutter_tools/templates/create/ios-swift.tmpl/Runner/AppDelegate.swift

@@ -7,7 +7,7 @@ import Flutter
     _ application: UIApplication,
     didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?
   ) -> Bool {
-    GeneratedPluginRegistrant.register(with: self);
-    return super.application(application, didFinishLaunchingWithOptions: launchOptions);
+    GeneratedPluginRegistrant.register(with: self)
+    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
   }
 }

packages/flutter_tools/templates/plugin/ios-swift.tmpl/Classes/SwiftpluginClass.swift.tmpl

@@ -3,12 +3,12 @@ import UIKit
     
 public class Swift{{pluginClass}}: NSObject, FlutterPlugin {
   public static func register(with registrar: FlutterPluginRegistrar) {
-    let channel = FlutterMethodChannel(name: "{{projectName}}", binaryMessenger: registrar.messenger());
-    let instance = Swift{{pluginClass}}();
-    registrar.addMethodCallDelegate(instance, channel: channel);
+    let channel = FlutterMethodChannel(name: "{{projectName}}", binaryMessenger: registrar.messenger())
+    let instance = Swift{{pluginClass}}()
+    registrar.addMethodCallDelegate(instance, channel: channel)
   }
 
   public func handle(_ call: FlutterMethodCall, result: @escaping FlutterResult) {
-    result("iOS " + UIDevice.current.systemVersion);
+    result("iOS " + UIDevice.current.systemVersion)
   }
 }