support for '@' symbol in dark mode

[CoderTag]

I have chosen Python in Gutenberg editor. In python i have used '@' symbol as decorator in the code. and I have used dark mode. while displaying '@mock' background and font end text both becoming dark, So can not see the code in the browser.

@mock.patch("mock_function.randint", return_value=2, autospec=True) def test_mock(v): assert abc(2) == 4