gui: mainwindow: Add menu action to open web user manual

gui/mainwindow.cpp

@@ -171,6 +171,9 @@ void MainWindow::connectSignals()
 	connect(ui->menuAboutQtAction, &QAction::triggered, this,
 			[this](bool checked) { QMessageBox::aboutQt(this, "About Qt"); });
 	connect(ui->menuSyncIndexAction, &QAction::triggered, this, &MainWindow::startIndexSync);
+	connect(ui->menuOpenUserManualAction, &QAction::triggered, this,
+			[this]() { QDesktopServices::openUrl(Common::userManualUrl()); });
+
 	connect(indexSyncer, &IndexSyncer::finished, this,
 			[&](unsigned int totalUpdated, unsigned int totalDeleted, unsigned int totalErrored)
 			{

gui/mainwindow.ui

@@ -626,6 +626,7 @@
      <string>looqs</string>
     </property>
     <addaction name="menuSyncIndexAction"/>
+    <addaction name="menuOpenUserManualAction"/>
     <addaction name="menuAboutAction"/>
     <addaction name="menuAboutQtAction"/>
     <addaction name="separator"/>
@@ -647,6 +648,11 @@
     <string>Sync index (remove deleted, update existing files)</string>
    </property>
   </action>
+  <action name="menuOpenUserManualAction">
+   <property name="text">
+    <string>Open user manual</string>
+   </property>
+  </action>
  </widget>
  <layoutdefault spacing="6" margin="11"/>
  <resources/>