fixed minor issues

src/util/QStringHash.hpp

@@ -0,0 +1,16 @@
+#pragma once
+
+#include <QHash>
+#include <QString>
+
+namespace std {
+
+template <>
+struct hash<QString> {
+    std::size_t operator()(const QString &s) const
+    {
+        return qHash(s);
+    }
+};
+
+}  // namespace std