Rename vignettes

[ryantibs]

So that they will appear in the order we want them to.

[ryantibs]

@capnrefsmmat I didn't mean to include the first commit f279444, that was a branch mistake (I branched from my covidhub-eval branch). But that branch should be merged into main anyway, per #240. Once Katie merges that, you can just merge this one, to save yourself a cherry-picking task.

[ryantibs]

@capnrefsmmat I just fixed the correlation vignette to study case and death rates (rather than counts), since the former is the only thing that makes sense for "sliced by time". (Oops! what a goof.) And for "sliced by location", they're equivalent.

Note: I force added the html file to save you from rerunning it, since it takes so long to knit. You can see I rewrote the text a bit because the results changed. You can delete the html file from the repo once you've looked at it.

[capnrefsmmat]

FYI adding the HTML is unnecessary, since I have to rebuild the vignette to make the pkgdown site anyway. Soon #266 will make the vignette super-fast and this won't be a problem.

I'll rebuild the site, check the result, and merge this in.

[ryantibs]

Thanks! (I just meant to add the html so you could look at it right away, and if you spotted anything, you could reply without needing to rebuild the pkgdown site.)