Create anchors for markdown headers

[epage]

trafficstars

See https://www.getzola.org/documentation/content/linking/ for ideas

We could go a step further and offer a variable on the post that allows someone to iterate over all the anchors and their titles. The downside is that I expect we'd only do this for markdown and not html because (1) trying to know if a page is html or not is dubious and (2) trying to infer anchors and their titles from random html seems dubious

[Geobert]

Isn't this part of https://github.com/cobalt-org/cobalt.rs/issues/440 ?

[epage]

I think anchors are independent of internal linking despite Zola documenting them together.