Removes the last line of the document.

def remove_last_line(self):
        """Removes the last line of the document."""
        editor = self._editor
        text_cursor = editor.textCursor()
        text_cursor.movePosition(text_cursor.End, text_cursor.MoveAnchor)
        text_cursor.select(text_cursor.LineUnderCursor)
        text_cursor.removeSelectedText()
        text_cursor.deletePreviousChar()
        editor.setTextCursor(text_cursor)