[T.F 2.0 API Docs] Adding to the documentation of tf.math.acos and tf.math.add functions

[Harsh188]

PR for issue #25802.

This PR is similar to #26017 and #25802. However, neither of them were merged.

I have attempted to add improvements to the documentation for tf.math.acos as well as tf.math.add.
This is my first contribution so please do help me identify and fix any errors I might have made.

Thank you

[mihaimaruseac]

The base_api documentation is available cross language bindings. Python examples should be inserted in Python documentation only, using testable docstrings to ensure that the examples stay in line with code changes.

https://www.tensorflow.org/community/contribute/docs_ref

[mihaimaruseac]

See 8582a58 for how to expose to Python and add documentation there, as an example

[Harsh188]

The base_api documentation is available cross language bindings. Python examples should be inserted in Python documentation only, using testable docstrings to ensure that the examples stay in line with code changes.

https://www.tensorflow.org/community/contribute/docs_ref

Whoops, I saw your comment on #25802 however I didn't quite understand the significance of the issue. Thank you for clarifying once again.
I will be removing the python examples from the base_api documentation and resubmit for review. I will then open another PR to add documentation to python/ops/math_ops.py.

[Harsh188]

Pinging @mihaimaruseac for review.
I'm assuming that along with adding examples to python/ops/math_ops.py, I will similarly have to do the same to core/ops/math_ops.cc.

[Harsh188]

Created a PR #42619 to address changes to the python documentation.