QtSupport: Pass const value by reference

Change-Id: Ibb99ad400a7be9942924abe369c6088be98ad9ec
Reviewed-by: Daniel Teske <daniel.teske@digia.com>

src/plugins/qtsupport/qtoutputformatter.cpp

@@ -173,7 +173,7 @@ void QtOutputFormatter::appendMessage(const QString &txt, Utils::OutputFormat fo
     cursor.endEditBlock();
 }
 
-void QtOutputFormatter::appendLine(QTextCursor &cursor, LinkResult lr,
+void QtOutputFormatter::appendLine(QTextCursor &cursor, const LinkResult &lr,
     const QString &line, Utils::OutputFormat format)
 {
     const QTextCharFormat normalFormat = charFormat(format);

src/plugins/qtsupport/qtoutputformatter.h

@@ -75,7 +75,7 @@ private slots:
 
 private:
     LinkResult matchLine(const QString &line) const;
-    void appendLine(QTextCursor &cursor, LinkResult lr, const QString &line,
+    void appendLine(QTextCursor &cursor, const LinkResult &lr, const QString &line,
                     Utils::OutputFormat);
 
     mutable QRegExp m_qmlError;