I still need to move the example from whats_new to a more appropriate place. Other than that, if I didn't mess up the rebase, it should be close to ready, at long last.

I left a modified example in the whats_new entry; it wasn't clear to me whether it should stay or go. I also modified the colormapnorms tutorial to add a panel illustrating the new kwarg, and to improve its overall clarity in the BoundaryNorm section (I think).

Since this is a rebase (with a little tune-up) of an old PR that still had a v3.3 milestone, I added that milestone here; but this is by no means a blocker. Anyone who wants to punt it to 3.4 is welcome to do so.

I can't see the examples in the docs.... Is there a reason sometimes the artifacts link doesn't work?

The link doesn't work because @efiring has CircleCI enabled on his fork, and the linker assumes builds are done on the main repo. You can still find the docs by going to the regular build and clicking the Artifacts tab.

With CircleCI disabled on my fork now, I am closing and re-opening this to trigger the builds.

See https://37861-1385122-gh.circle-artifacts.com/0/doc/build/html/tutorials/colors/colormapnorms.html#discrete-bounds for the modified tutorial.