Update simbad.rst
While the previous query might have worked, the docs at clearly say "Epoch must be prefixed by 'B' or 'J'." Thus, I fixed the example to follow that rule.
@@ -677,7 +677,7 @@ be specified as follows (e.g. epoch of J2017.5 and equinox of 2000):
.. code-block:: python
- >>> customSimbad.add_votable_fields('ra(2;A;ICRS;J2017.5;2000)', 'dec(2;D;ICRS;2017.5;2000)')
+ >>> customSimbad.add_votable_fields('ra(2;A;ICRS;J2017.5;2000)', 'dec(2;D;ICRS;J2017.5;2000)')
>>> customSimbad.remove_votable_fields('coordinates')
>>> customSimbad.query_object("HD189733")
<Table masked=True length=1>
