Add plugin url_launcher for Help page.

macos/Flutter/GeneratedPluginRegistrant.swift

@@ -7,8 +7,10 @@ import Foundation
 
 import path_provider_foundation
 import sqflite_darwin
+import url_launcher_macos
 
 func RegisterGeneratedPlugins(registry: FlutterPluginRegistry) {
   PathProviderPlugin.register(with: registry.registrar(forPlugin: "PathProviderPlugin"))
   SqflitePlugin.register(with: registry.registrar(forPlugin: "SqflitePlugin"))
+  UrlLauncherPlugin.register(with: registry.registrar(forPlugin: "UrlLauncherPlugin"))
 }