Formatting issues in Formatting docs

[ndiego]

I stumbled upon a few formatting issues related to how the markdown on GitHub is ingested into the actual https://make.wordpress.org/docs site.

There are probably more, but here are a few.

Headings and titles	Units of measurement	Media

[!Note] While the callout design has been updated recently, the functionality is the same as the previous design, so this does not appear to be a new issue.

[tacitonic]

I had added a list in an earlier issue: https://github.com/WordPress/WordPress-Documentation-Style-Guide/issues/12 I'll update it to add the Units of Measurement page as well.