Fix Read the Docs warning failures

[JanOstrowka]

Summary

• change the README title to a real Markdown H1 so MyST no longer reports top-level heading warnings
• skip inherited from_bytes and to_bytes members in autodoc to avoid Python 3.9 enum docstring warnings in RTD

Verification

• reproduced the hosted RTD toolchain locally with Sphinx 7.4.7 and myst-parser 3.0.1
• ran sphinx-build -b html -W docs /tmp/python-miio-rtd-rtd74-html successfully

This is intended as a standalone docs/build cleanup so feature PRs are not blocked by pre-existing RTD failures.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.26%. Comparing base (c5cc0f2) to head (96eb689).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #2070   +/-   ##
=======================================
  Coverage   82.26%   82.26%           
=======================================
  Files         197      197           
  Lines       19145    19145           
  Branches     1052     1052           
=======================================
  Hits        15750    15750           
  Misses       3218     3218           
  Partials      177      177           

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[syssi]

I agree to pin poetry to keep the Python 3.9 Windows build for now.