Add units to parameter definitions

The purpose of this MR is to add units to the parameter definitions table in the documentation.

cc @nathan-johnson-mcdaniel

docs/gw/SamplesDict.rst

@@ -24,6 +24,17 @@ these descriptions directly from the `SamplesDict` class,
     >>> print(parameters[0].description)
     the detector-frame (redshifted) mass of the heavier object
 
+Additional information about specific parameters can be found through the
+:code:`information` property,
+
+.. code-block:: python
+
+    >>> print(parameters[0].information)
+    Parameter: mass_1
+    Description: the detector-frame (redshifted) mass of the heavier object
+    Unit: Solar mass
+    Latex: $m_{1}$
+
 Source classifications
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