add JPL horizons to docs index
@@ -220,6 +220,7 @@ These others are functional, but do not follow a common & consistent API:
nasa_exoplanet_archive/nasa_exoplanet_archive.rst
exoplanet_orbit_database/exoplanet_orbit_database.rst
oac/oac.rst
+ jplhorizons/jplhorizons.rst
Catalog, Archive, and Other
===========================
