Footnotes are still duplicated if they're in a list

[iximeow]

i assume this is something similar to #14, but i don't see anything super obvious so an issue is probably better than me trying to chase further. here's a quasi-RFD for your consideration:

:showtitle:
:toc: left
:numbered:
:icons: font
:state: published
:discussion:
:revremark: State: {state} | {discussion}
:authors: iximeow <iximeow@oxide.computer>

= RFD 540 Footnotes are still duplicated sometimes
{authors}

The footnote in the following list should be `[1]` instead of `[2]`:

* Hello today we are here to add one (1) footnote. footnote:[this is the
  first and only footnote in the document.]

== Determinations

* The single item list above has a footnote titled `[2]`.
* Rendered footnotes should have a 1-1 relationship with footnotes in the
  source doc.

it does this:

[benjaminleonard]

Thanks, I should have moved this oxidecomputer/rfd-site#109 over here.

We're no longer caching the getContent response, because now in theory it should only run once within the pre-processor. But clearly there's some shenanigans going on!