Theme: How do I add a link to the header next to each header?

[jtagcat]

Like on GitHub, and on other sites, there’s a link button often left of the header:

While hovering over a header, icon appears. The icon links to the header (with ID).

How do I achive that in my theme?

[bep]

gohugoio/gohugoioTheme/blob/master/layouts/_default/_markup/render-heading.html

[jtagcat]

There doesn’t seem to be anything disabling it from appearing. I couldn’t figure out the reason why for example Hermit does render the header link, yet Plains doesn’t.

[pointyfar]

You have to add the feature, either as render-heading as in the Hugo theme, or similar to how the Hermit theme does it in this line: https://github.com/Track3/hermit/blob/master/layouts/posts/single.html#L26