ClangTools: Add using for QList<Diagnostics>

Change-Id: Ie7978fc33386d083b786ad75b3b6700125b11fec
Reviewed-by: Cristian Adam <cristian.adam@qt.io>
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/clangtools/clangtoolsdiagnostic.h

@@ -62,6 +62,8 @@ public:
     bool hasFixits = false;
 };
 
+using Diagnostics = QList<Diagnostic>;
+
 quint32 qHash(const Diagnostic &diagnostic);
 
 } // namespace Internal