Various Plugins: Simplify return QStringList statements

Change-Id: Id014225851e6b9f8436387c681bea42e5de3b797
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

src/plugins/vcsbase/vcsbasesubmiteditor.cpp

@@ -385,7 +385,7 @@ SubmitFileModel *VcsBaseSubmitEditor::fileModel() const
 QStringList VcsBaseSubmitEditor::rowsToFiles(const QList<int> &rows) const
 {
     if (rows.empty())
-        return QStringList();
+        return {};
 
     QStringList rc;
     const SubmitFileModel *model = fileModel();