Fixing docs warnings

[mohanad0mohamed]

Fixes #20

• All warnings have been fixed and tested locally.
• It seems like there are some edits to be able to be merged with main.

[mohanad0mohamed]

Before merging this pull request, These pull requests https://github.com/google/globalfoundries-pdk-ip-gf180mcu_fd_ip_sram/pull/5 and https://github.com/google/globalfoundries-pdk-libs-gf180mcu_fd_io/pull/2 should be merged first to solve 7 warnings found in this build https://gf180mcu-pdk--35.org.readthedocs.build/en/35/

[mohanad0mohamed]

This PR should be merged after all these:

• google/open-source-pdks#18
• https://github.com/google/gf180mcu-pdk/pull/39
• google/globalfoundries-pdk-ip-gf180mcu_fd_ip_sram#8
• google/globalfoundries-pdk-libs-gf180mcu_fd_io#4
• google/globalfoundries-pdk-libs-gf180mcu_fd_sc_mcu7t5v0#8
• google/globalfoundries-pdk-libs-gf180mcu_fd_sc_mcu9t5v0#11

[mohanad0mohamed]

Renamed the extension of role as in https://github.com/google/open-source-pdks/pull/18

[mohanad0mohamed]

Latest update: this PR should be merged after all these:

• google/open-source-pdks#18
• https://github.com/google/gf180mcu-pdk/pull/39
• google/globalfoundries-pdk-libs-gf180mcu_fd_sc_mcu7t5v0#8
• google/globalfoundries-pdk-libs-gf180mcu_fd_sc_mcu9t5v0#11
• https://github.com/google/globalfoundries-pdk-libs-gf180mcu_fd_sc_mcu7t5v0/pull/9
• https://github.com/google/globalfoundries-pdk-libs-gf180mcu_fd_sc_mcu9t5v0/pull/12

[mohanad0mohamed]

Added exclusion of code-of-conduct.rst and contributing.rst in conf.py

[mithro]

The docs build is also failing with

Running Sphinx v5.1.1
fatal: --unshallow on a complete repository does not make sense

Traceback (most recent call last):
  File "/home/docs/checkouts/readthedocs.org/user_builds/gf180mcu-pdk/envs/35/lib/python3.7/site-packages/sphinx/registry.py", line 442, in load_extension
    mod = import_module(extname)
  File "/home/docs/checkouts/readthedocs.org/user_builds/gf180mcu-pdk/envs/35/lib/python3.7/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1006, in _gcd_import
  File "<frozen importlib._bootstrap>", line 983, in _find_and_load
  File "<frozen importlib._bootstrap>", line 965, in _find_and_load_unlocked
ModuleNotFoundError: No module named 'sphinx_pdk_roles'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/home/docs/checkouts/readthedocs.org/user_builds/gf180mcu-pdk/envs/35/lib/python3.7/site-packages/sphinx/cmd/build.py", line 276, in build_main
    args.pdb)
  File "/home/docs/checkouts/readthedocs.org/user_builds/gf180mcu-pdk/envs/35/lib/python3.7/site-packages/sphinx/application.py", line 222, in __init__
    self.setup_extension(extension)
  File "/home/docs/checkouts/readthedocs.org/user_builds/gf180mcu-pdk/envs/35/lib/python3.7/site-packages/sphinx/application.py", line 400, in setup_extension
    self.registry.load_extension(self, extname)
  File "/home/docs/checkouts/readthedocs.org/user_builds/gf180mcu-pdk/envs/35/lib/python3.7/site-packages/sphinx/registry.py", line 446, in load_extension
    err) from err
sphinx.errors.ExtensionError: Could not import extension sphinx_pdk_roles (exception: No module named 'sphinx_pdk_roles')

Extension error:
Could not import extension sphinx_pdk_roles (exception: No module named 'sphinx_pdk_roles')
Docs dir is: /home/docs/checkouts/readthedocs.org/user_builds/gf180mcu-pdk/checkouts/35/docs