Re-make the vignette about PR functions

[jennybc]

Some of the rendered output will look different after the general master to main switch (once #1480 is closed).

This basically amounts to walking through these steps again and updating our static "account" of what the various role players would see.

[malcolmbarrett]

If @gadenbuie is up for contributing, I think we should consider incorporating his great usethis PR flow chart

[jennybc]

Yes I would love to feature that flow chart anywhere and everywhere it fits here.

[gadenbuie]

Thank you both! I'd be happy to have the flow chart appear in the PR functions vignette or wherever you see fit. There are editable versions and raster images of the flow chart in my blog post (I used draw.io) but please let me know if I can help in any way.

[jennybc]

It's open season on this one, now that master --> main has happened.