Avoid D103 linter warnings via script.py.mako

[peterjc]

Closes #1567

Description

This will silence the commonly used pydocstyle D103 warnings from flake8 or ruff check:

• http://www.pydocstyle.org/en/stable/error_codes.html#grouping
• https://docs.astral.sh/ruff/rules/undocumented-public-function/

Checklist

This pull request is:

• [ ] A documentation / typographical error fix
  • Good to go, no issue or tests are needed
• [x] A short code fix
  • please include the issue number, and create an issue if none exists, which must include a complete example of the issue. one line code fixes without an issue and demonstration will not be accepted.
  • Please include: Fixes: #<issue number> in the commit message
  • please include tests. one line code fixes without tests will not be accepted.
• [ ] A new feature implementation
  • please include the issue number, and create an issue if none exists, which must include a complete example of how the feature would look.
  • Please include: Fixes: #<issue number> in the commit message
  • please include tests.

Have a nice day!

[sqla-tester]

New Gerrit review created for change fa3bcd5926cc2523ac6f05c3c1e8c4eeafc55dda: https://gerrit.sqlalchemy.org/c/sqlalchemy/alembic/+/5584