DM-22207:Update doc string to specify this works on classes as well as functio…

[leannep]

No description provided.

[jonathansick]

Although the summary sentence is updated, I wonder if the rest of the docstrings also needs some treatment?

For instance, add an example of deprecating a class?

Note that the syntax for the example in this docstring is also wrong (from before). It should be:

Examples
--------
.. code-block:: python

   ExposureF.getCalib = deprecate_pybind11(ExposureF.getCalib,
       reason="Replaced by getPhotoCalib. (Will be removed in 18.0)",
       category=FutureWarning))

(pluralization of "Examples" and the code-block to style the example)

[jonathansick]

Looking at this again, because deprecate_pybind11 isn't a decorator, we should document the func parameter, and perhaps rename it so something more general like obj.

Parameters
----------
obj : function, method, or class
    The function, method, or class to deprecate.

I would also recommend renaming the func parameter to obj.