Fixed #23148 -- Minor tweaks in tutorial code samples
Fixed two typos in docstrings.
Updated MySQL links to version 5.6.
Fixed #23144 -- Dropped support for MySQL 5.0, 5.1.
Fixed #23149 -- Clarified note on HTTPOnly in cookie-based session docs
Fixed #23154 -- Removed reference to deprecated run_gunicorn command.

Thanks frewsxcv for the report.
Removed notes for versions of SQLite older than 5 years.