Revert "Use QComboBox::currentTextChanged instead of currentIndexChanged"

This reverts commit 25f9d9c434.

The deprecation was reverted in qtbase 298f750cdba2bd15e735a47ba8d3b9c093367ba3.

Change-Id: I8a05f038be4b7fc89e05830435e08c3212e4f116
Reviewed-by: hjk <hjk@qt.io>

src/shared/help/bookmarkmanager.cpp

@@ -95,7 +95,8 @@ BookmarkDialog::BookmarkDialog(BookmarkManager *manager, const QString &title,
             &QStandardItemModel::itemChanged,
             this, &BookmarkDialog::itemChanged);
 
-    connect(ui.bookmarkFolders, &QComboBox::currentTextChanged,
+    connect(ui.bookmarkFolders,
+            QOverload<const QString &>::of(&QComboBox::currentIndexChanged),
             this, &BookmarkDialog::selectBookmarkFolder);
 
     connect(ui.treeView, &TreeView::customContextMenuRequested,