Allow for grouping extended characters

https://invent.kde.org/mglebocki/konsole complex-scripts-support
CCBUG: 401094

src/TerminalDisplay.cpp

@@ -1609,7 +1609,10 @@ void TerminalDisplay::drawContents(QPainter& paint, const QRect& rect)
                 return (_image[characterLoc].character == 0) == doubleWidth;
             };
             const auto canBeGrouped = [&](int column) {
-                return _image[loc(column, y)].character <= 0x7e || rtl || malayalam(column);
+                return _image[loc(column, y)].character <= 0x7e
+                       || (_image[loc(column, y)].rendition & RE_EXTENDED_CHAR)
+                       || rtl
+                       || malayalam(column);
             };
 
             if (canBeGrouped(x)) {