### Bug summary generate axes by axisartist.Subplot can not modify xlabel's fontsize and location what can be done across generate axes by plt.subplots ### Code for reproduction ```python import matplotlib.pyplot as plt import mpl_toolkits.axisartist as axisartist fig = plt.figure() ax = axisartist.Subplot(fig, 111) fig.add_axes(ax) ax.set_xlabel('t', loc='right', fontsize=15) ax.set_xticks([]) plt.show() ``` ### Actual outcome  ### Expected outcome  ### Additional information _No response_ ### Operating system Windows ### Matplotlib Version 3.4.3 ### Matplotlib Backend module://matplotlib_inline.backend_inline ### Python version 3.9.7 ### Jupyter version 6.4.5 ### Installation _No response_