Add check for undocumented names; remove a dangling exported function

[pjaap]

No description provided.

[pjaap]

I'll fix the documentation problem

[pjaap]

Hmm, CI complaines that GridVisualize.GridVisualize is not in the docs. That is true. But I wanted to use the README as documentation for this. Where do I put this in the docs?

[jpthiele]

We could do an allindex.md similar to how VoronoiFVM does it https://wias-pdelib.github.io/VoronoiFVM.jl/stable/allindex/
inside the public api part of docs.

[j-fu]

I always would put the module doc on top of docs/src/index.md

[jpthiele]

I solved it in GridVisualizeTools like this WIAS-PDELib/GridVisualizeTools.jl@d94e632

@j-fu, did you check the resulting docs to see if you like how the result looks?

[j-fu]

I checked the docs locally, it works.

[jpthiele]

Good.
Can we remove the unrelated formatting commit from this PR? or move it to #57 ?

[j-fu]

this is just the pluto notebook thing. I think it is not worth to bother that much about this. I would just keep it here, if you want to move it, it's ok as well.

[jpthiele]

I have removed the unrelated change to examples/plutovista.jl from 'update index.md' and with it the wrong format introduced therein.

[pjaap]

Should be good now