Terminal: Auto-scroll when selecting outside

Change-Id: I5dea3256524634d9c3e6c0f8132c6bdba4494978
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Cristian Adam <cristian.adam@qt.io>

src/plugins/terminal/terminalwidget.h

@@ -89,8 +89,6 @@ protected:
     void mouseReleaseEvent(QMouseEvent *event) override;
     void mouseDoubleClickEvent(QMouseEvent *event) override;
 
-    void scrollContentsBy(int dx, int dy) override;
-
     void showEvent(QShowEvent *event) override;
 
     bool event(QEvent *event) override;
@@ -189,6 +187,9 @@ private:
 
     QTimer m_flushDelayTimer;
 
+    QTimer m_scrollTimer;
+    int m_scrollDirection{0};
+
     std::array<QColor, 18> m_currentColors;
 
     Utils::Terminal::OpenTerminalParameters m_openParameters;