Add xaxis and yaxis attributes to Axes docs

Author: timhoffm

doc/api/axes_api.rst

@@ -274,6 +274,8 @@ Axis / limits
    :template: autosummary.rst
    :nosignatures:
 
+   Axes.xaxis
+   Axes.yaxis
    Axes.get_xaxis
    Axes.get_yaxis
 

lib/matplotlib/axes/_base.py

@@ -566,6 +566,12 @@ class _AxesBase(martist.Artist):
     dataLim: mtransforms.Bbox
     """The bounding `.Bbox` enclosing all data displayed in the Axes."""
 
+    xaxis: maxis.XAxis
+    """The x-axis."""
+
+    yaxis: maxis.YAxis
+    """The y-axis."""
+
     @property
     def _axis_map(self):
         """A mapping of axis names, e.g. 'x', to `Axis` instances."""