Summary

Contributing small docs changes has one bottleneck in my perception: CircleCI takes LONG to build new changes in examples.
When I execute the python script locally, it takes about 0.2 seconds.
The CircleCI docs build takes more than 30 minutes.
I know that the sphinx rendering must also take some seconds, but it would be amazing if there was a way to bring the build time down to e.g. only 1 minute by only rendering relevant parts of the docs.
This could accelerate the review process a lot.

Proposed fix

Here is an idea: Only nodes that connect to green lines are rendered, everything else is ignored.

In a pull request, it can look like this: In every new commit, the (not yet existing?) GitHub action Build changes only docs is triggered.
This action will execute the above diagram.

For the current complete docs build with CircleCI, I see two options:

1. It could be additional active all the time.
2. It could be activated after the iteration phase in the last commit, to make sure that the whole docs build without error. This activation could be triggered e.g. when a pull request is getting the "Approved" status, or when there is a certain keyword in the commit. I would prefer the later one, as this saves resources.

Note, that this is issue is not a Matplotlib specific, but also applies to other rendering intensive docs like napari, manim and scikit-image.