HIV Guidance Document - Add a Table of Contents

[frankambrosio3]

📌 Explain the Request

We would like a table of contents added to the HIV Guidance document with links to all sections.

📚 Context

Currently the document is a bit difficult to navigate for a newer github user, so a table of contents would enhance accessibility.

📈 Desired Contribution

A fork of the main PHA4GE repo including Markdown code adding a table of contents to the HIV Guidance Document.

ℹ️ Additional Information

https://github.blog/changelog/2021-04-13-table-of-contents-support-in-markdown-files/

[MarcNiebel]

This has been completed by @frankambrosio3 #55