fix(utils): parse Markdown headings with CRLF line break

[Josh-Cena]

Motivation

Fix #7044

Have you read the Contributing Guidelines on pull requests?

Yes

Test Plan

Added two tests

[netlify]

✅ [V2]

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[github-actions]

⚡️ Lighthouse report for the changes in this PR:

Category	Score
🟠 Performance	64
🟢 Accessibility	100
🟢 Best practices	92
🟢 SEO	100
🟢 PWA	90

Lighthouse ran on https://deploy-preview-7043--docusaurus-2.netlify.app/

[github-actions]

Size Change: 0 B

Total Size: 807 kB

ℹ️ View Unchanged

Filename	Size
website/.docusaurus/globalData.json	49.9 kB
website/build/assets/css/styles.********.css	105 kB
website/build/assets/js/main.********.js	613 kB
website/build/index.html	38.4 kB

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[cp2004]

So glad I managed to find this PR quickly! That explains some things that definitely confused me...