Add support for subsections in the API

[wise-king-sullyman]

Currently documentation with a subsection frontmatter entry is missing that subsection in the API.

This is particularly problematic for i.e. extensions where each extension is differentiated using the subsection rather than the section.

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Jira Issue: PF-3174

[github-actions]

🎉 This issue has been resolved in version 1.19.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀