Fixing warnings

[mohanad0mohamed]

Fixes https://github.com/google/gf180mcu-pdk/issues/20

• Changed an error in gf180mcu_fd_sc_mcu9t5v0__addf_1.rst related to an image reference.

• [x] Built locally successfully

[mohanad0mohamed]

That's why I renamed those files:

[mohanad0mohamed]

@mithro I have retrieved the code-of-conduct.rst and contributing.rst after excluding them in conf.py