h4-h6 headings are not getting anchor link.

[StevenDufresne]

We link headings based on their appearance in the Table of Contents (source).

However, we want to link all headings for easy sharing.

How to reproduce

1. Visit a developer resource page
2. Notice not all headings have shareable link
   a. Try looking for "Default webpack config" in the link about

[ryelle]

+1 for making the headings linkable, but by default this would also add those to the Table of Contents, and I don't think that would be helpful.

[StevenDufresne]

I agree, being linked in the document shouldn't make them show up in the Table of Contents.