This uses a new feature from snapbox that let's us render terminal
styling in SVG files. This let's us see / visualize ANSI escape codes,
including in github's UI (will render images, including side-by-side
images for diffs).
This just gets rid of irrelevant packages in the registry. Looking into
which versions aren't needed would require a deeper pass, so I held off
on that for now.
Before, the tests were in the 300-500ms range and now they take
100-300ms.
This did call to my attention that `unrelated` is misspelled as
`unrelateed` but holding off on fixing that to reduce conflicts.
In writing the contrib documentation for functional vs ui tests, I
realized that as we work to make snapbox work for the functional tests,
we'll need distinct `Assert` objects since we'll want to elide a lot
more content in functional tests. I'm making room for this by
qualifying the existing asserts as being for "ui".
