Make breadcrumbs clickable in the references docs

[runleonarun]

Contributions

• I have read the contribution docs, and understand what's expected of me.

Link to the page on docs.getdbt.com requiring updates

All references pages, for example:
persist docs

What part(s) of the page would you like to see updated?

Fix the references section to include landing pages for every folder so the bread crumbs are clickable. This means we need all categories to include links to landing pages, for example "About such and such" pages.

Additional information

Here's our previous work on breadcrumbs: #3515