add shxarray to the xarray ecosystem list (#9995)

Author: strawpants

doc/ecosystem.rst

@@ -38,6 +38,7 @@ Geosciences
 - `salem <https://salem.readthedocs.io>`_: Adds geolocalised subsetting, masking, and plotting operations to xarray's data structures via accessors.
 - `SatPy <https://satpy.readthedocs.io/>`_ : Library for reading and manipulating meteorological remote sensing data and writing it to various image and data file formats.
 - `SARXarray <https://tudelftgeodesy.github.io/sarxarray/>`_: xarray extension for reading and processing large Synthetic Aperture Radar (SAR) data stacks.
+- `shxarray <https://shxarray.wobbly.earth/>`_: Convert, filter,and map geodesy related spherical harmonic representations of gravity and terrestrial water storage through an xarray extension.
 - `Spyfit <https://spyfit.readthedocs.io/en/master/>`_: FTIR spectroscopy of the atmosphere
 - `windspharm <https://ajdawson.github.io/windspharm/index.html>`_: Spherical
   harmonic wind analysis in Python.