Replace flake8-rst with flake8-rst-docstrings

[ErfanShokrollahzadeh]

Fixes #46865

Replace flake8-rst with flake8-rst-docstrings for running flake8 on code snippets in rst files.

• pyproject.toml

  • Remove flake8 from the tool.ruff.lint section.
  • Add flake8-rst-docstrings to the tool.ruff.lint section.
  • Update the tool.ruff.lint section to use flake8-rst-docstrings instead of flake8-rst.

• .pre-commit-config.yaml

  • Remove the flake8-rst hook from the hooks section.
  • Add a new hook for flake8-rst-docstrings in the hooks section.
  • Configure the new flake8-rst-docstrings hook with appropriate additional_dependencies.

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