fix docs

[Khabib73]

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

The documentation build generates the following warnings:

(venv) ~/ydb-python-sdk sphinx-build -b html docs docs/_build/html -q
/Users/khabibshahbanov/ydb-python-sdk/docs/driver.rst:2: WARNING: Duplicate explicit target name: "full example".
/Users/khabibshahbanov/ydb-python-sdk/docs/driver.rst:2: WARNING: Duplicate explicit target name: "full example".
/Users/khabibshahbanov/ydb-python-sdk/docs/driver.rst:2: WARNING: Duplicate explicit target name: "full example".
/Users/khabibshahbanov/ydb-python-sdk/docs/driver.rst:2: WARNING: Duplicate explicit target name: "full example".
/Users/khabibshahbanov/ydb-python-sdk/docs/driver.rst:2: WARNING: Duplicate explicit target name: "full example".
WARNING: unsupported theme option 'fixed_sidebar' given
WARNING: unsupported theme option 'page_width' given
WARNING: unsupported theme option 'show_related' given
WARNING: unsupported theme option 'show_powered_by' given

What is the new behavior?

Fix Sphinx warnings: remove unsupported html_theme_options and convert duplicate named links to anonymous ones. Added html_show_sphinx = False to hide the "Built with Sphinx" footer line, matching the deployed docs.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.37%. Comparing base (8ce506e) to head (4d6cf38).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #894   +/-   ##
=======================================
  Coverage   82.36%   82.37%           
=======================================
  Files          99       99           
  Lines       12753    12753           
  Branches     1242     1242           
=======================================
+ Hits        10504    10505    +1     
+ Misses       1795     1794    -1     
  Partials      454      454           

Flag	Coverage Δ
integration	80.20% <ø> (+<0.01%)	⬆️
unit	48.57% <ø> (ø)

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see 1 file with indirect coverage changes

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