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/git/branchmodel.cpp

@@ -543,8 +543,7 @@ QString BranchModel::fullName(const QModelIndex &idx, bool includePrefix) const
 QStringList BranchModel::localBranchNames() const
 {
     if (!d->rootNode || !d->rootNode->count())
-        return QStringList();
-
+        return {};
     return d->rootNode->children.at(LocalBranches)->childrenNames() + d->obsoleteLocalBranches;
 }