Port to PyQt6

Author: manateelazycat

buffer.py

@@ -19,8 +19,8 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-from PyQt5.QtGui import QColor
-from PyQt5.QtCore import QUrl, QTimer
+from PyQt6.QtGui import QColor
+from PyQt6.QtCore import QUrl, QTimer
 from core.webengine import BrowserBuffer
 from core.utils import interactive
 from functools import cmp_to_key