Make Python minimum version requirement an argument

src/gui/mainwindow.cpp

@@ -1887,15 +1887,15 @@ void MainWindow::on_actionSearchWidget_triggered()
 
 #ifdef Q_OS_WIN
             const QMessageBox::StandardButton buttonPressed = QMessageBox::question(this, tr("Old Python Runtime")
-                , tr("Your Python version (%1) is outdated. Minimum requirement: 3.5.0.\nDo you want to install a newer version now?")
-                    .arg(pyInfo.version)
+                , tr("Your Python version (%1) is outdated. Minimum requirement: %2.\nDo you want to install a newer version now?")
+                    .arg(pyInfo.version, QLatin1String("3.5.0"))
                 , (QMessageBox::Yes | QMessageBox::No), QMessageBox::Yes);
             if (buttonPressed == QMessageBox::Yes)
                 installPython();
 #else
             QMessageBox::information(this, tr("Old Python Runtime")
-                , tr("Your Python version (%1) is outdated. Please upgrade to latest version for search engines to work.\nMinimum requirement: 3.3.0.")
-                .arg(pyInfo.version));
+                , tr("Your Python version (%1) is outdated. Please upgrade to latest version for search engines to work.\nMinimum requirement: %2.")
+                .arg(pyInfo.version, QLatin1String("3.5.0")));
 #endif
             return;
         }