`PolarAxes.get_rlim()` and `get_thetalim()` added#

PolarAxes now provides get_rlim and get_thetalim to complement the existing set_rlim and set_thetalim. Previously, one had to use Axes.get_ylim, Axes.get_xlim as a workaround.

ax = plt.subplot(projection="polar")
ax.set_rlim(1, 5)
rmin, rmax = ax.get_rlim()   # was: AttributeError

PolarAxes.get_rlim() and get_thetalim() added#