DOC/DEPR: eps_writer's documentation is misleading

[neutrinoceros]

In a recent ticket, it was brought up that the way eps_writer is advertised in docs may be misleading to newcomers. In particular, when browsing docs, one may look for Publication Ready Figures, and overlook everything else, missing that the functionality they need is actually built into SlicePlot and the likes.
I think it should be made clear in docs that eps_writer isn't our main API for saving image files, either by renaming this section or adding a warning to it.

It may also be that the subpackage is simply not relevant anymore now that matplotlib natively supports .pdf and .eps outputs.
I also note that there's an open ticket (#3498) to make eps_writer a solo extension package, but it hasn't received any attention that I know of. So what should be done with it ? From where I stand, it seems ripe for deprecation, but I may be missing reasons why not.