Set the cursor of an editor.

def set_editor_cursor(self, editor, cursor):
        """Set the cursor of an editor."""
        pos = cursor.position()
        anchor = cursor.anchor()

        new_cursor = QTextCursor()
        if pos == anchor:
            new_cursor.movePosition(pos)
        else:
            new_cursor.movePosition(anchor)
            new_cursor.movePosition(pos, QTextCursor.KeepAnchor)
        editor.setTextCursor(cursor)