Fix tooltip & popup positioning (#4740)

* Fix tooltip & popup positioning

This tries to ensure the tooltip & popups are created on the correct
monitor

* Add changelog entry

* Clean up debug output

* Use the full frame geometry to figure out screen bound movements

* Remove the now-unused `setStayInScreenRect` function

* Change the UserInfoPopup offset to be based on its width & height
instead

* Remove more debug output

src/widgets/splits/SplitHeader.cpp

@@ -964,7 +964,7 @@ void SplitHeader::enterEvent(QEvent *event)
         auto pos = this->mapToGlobal(this->rect().bottomLeft()) +
                    QPoint((this->width() - tooltip->width()) / 2, 1);
 
-        tooltip->moveTo(this, pos, false);
+        tooltip->moveTo(pos, false, BaseWindow::BoundsChecker::CursorPosition);
         tooltip->show();
     }