[Feature Request] Export as Markdown

[aphilas]

Is your feature request related to a problem? Please describe.

I always have to copy and paste (JSON) requests and response bodies for documenting manual verification steps of an API.

Describe the solution you'd like

I would like a feature to allow one to export the httpbook notebook to markdown (or other formats).

Describe alternatives you've considered

I've tried running requests and hitting save, but this does not save the response bodies: #148. Even if #148 is resolved, markdown still looks gnarly (e.g. /* ### test api*/) and would be more readable, and rendered correctly e.g. in GitHub PRs/VSCode as markdown.

Additional context

Jupyter notebooks in VSCode support export to py/pdf using the three-dots menu at the top of the notebook: https://code.visualstudio.com/docs/datascience/jupyter-notebooks#_export-your-jupyter-notebook

Created a rough PoC here: https://github.com/aphilas/httpbook-exporter. Sample output: https://github.com/aphilas/httpbook-exporter/blob/main/src/test/fixtures/output.md.