Exclude properties from the documentation

- I think it's good to have properties for beta and eps, so that we can check the values before assigning them, but I also think that the documentation of those properties is a bit bloating the documentation of the aggregator itself (and it's quite a duplicate of the documentation of the parameters). So IMO the best thing to do is to keep those two as properties, but not display the documentation of those properties (it still shows in the documentation of these parameters)

Author: ValerianRey

docs/source/docs/aggregation/gradvac.rst

@@ -6,9 +6,9 @@ GradVac
 .. autoclass:: torchjd.aggregation.GradVac
     :members:
     :undoc-members:
-    :exclude-members: forward
+    :exclude-members: forward, eps, beta
 
 .. autoclass:: torchjd.aggregation.GradVacWeighting
     :members:
     :undoc-members:
-    :exclude-members: forward
+    :exclude-members: forward, eps, beta