Bug report

From the image in the release notes for matplotlib 3.4 here:
https://matplotlib.org/stable/users/whats_new.html#date-formatters-now-respect-usetex-rcparam

The dateformatter does not use text mode for the month names but sets them like $Aug$. Which is bad typography, since it will be typeset as the mathematical expression A * u * g, not the text Aug.