Bump pymdown-extensions from 10.21 to 10.21.2

[dependabot]

Bumps pymdown-extensions from 10.21 to 10.21.2.

Release notes

Sourced from pymdown-extensions's releases.

10.21. 2

10.21.2

• FIX: Highlight: Latest Pygments versions cannot handle a "filename" for code block titles of None.

10.20.1

• FIX: Quotes: Ensure the first class for callouts (the alert type) is always rendered lowercase.

Commits

• a4fdd73 Skip tag 10.21.1 has we accidentally already used it
• 8afb4cd Docs: Update JS deps
• 7bf5b29 Pygments needs a non-None value for code block title (#2863)
• 20b11eb Fix some spelling and formatting
• c9edba3 Docs: strengthen Snippets warning and add security considerations
• See full diff in compare view

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