Fix `readme.rst`.
Tested locally by running `python setup.py doc`, no more errors from observability.
Only error is related to grpc_status:
```
WARNING: autodoc: failed to import module 'rpc_status' from module 'grpc_status'; the following exception was raised:
cannot import name 'status_pb2' from 'google.rpc' (unknown location)
```
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Closes#35988
PiperOrigin-RevId: 609820414
* Expose the C-Core API in Cython layer
* Handle the object translation
* Create a separate package for Channelz specifically
* Handle nullptr and raise exception if seen one
* Translate C++ Channelz unit tests
* Adding 5 more invalid query unit tests
Adding peripheral utility for grpcio-channelz package
* Add to `pylint_code.sh`
* Add to Python build script
* Add to artifact build script
* Add to Bazel
* Add to Sphinx module list
* Use templates instead of generating them every time
* Theme changed
* Add grpc_* modules
* APIs grouped
* No documentation for class members without docstring
* Add docstring for status code
Xuan Wang