DOC: adding docs and changelog

Author: bsipocz

CHANGES.rst

@@ -21,6 +21,12 @@ gaia
 
 - Update DR4 retrieval_type names and include the new one EPOCH_ASTROMETRY_BRIGHT [#3207]
 
+ipac.irsa
+^^^^^^^^^
+
+- Adding the "servicetype" kwarg to ``list_collections`` to be able to list SIA
+  and SSA collections separately. [#3200]
+
 ipac.nexsci.nasa_exoplanet_archive
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 

docs/ipac/irsa/irsa.rst

@@ -234,13 +234,15 @@ Enhanced Imaging products in the centre of the COSMOS field as an `~astropy.tabl
 
 To list available collections for SIA queries, the
 `~astroquery.ipac.irsa.IrsaClass.list_collections` method is provided, and
-will return a `~astropy.table.Table`:
+will return a `~astropy.table.Table`. You can use the ``servicetype``
+argument to filter for image or spectral collections using ``'SIA'`` or
+``'SSA'`` respectively:
 
 .. doctest-remote-data::
 
    >>> from astroquery.ipac.irsa import Irsa
-   >>> Irsa.list_collections()
-   <Table length=124>
+   >>> Irsa.list_collections(servicetype='SIA')
+   <Table length=104>
          collection
            object
    ---------------------