simple-repository-api: add PEP 792, clean up layout

[woodruffw]

This PR serves two purposes:

1. It integrates the recently-approved PEP 792 into the living PyPUG specifications, so that I can complete the procedural step of linking to PyPUG from the PEP itself

2. In the process of integrating this spec into the living simple repository API spec, I attempted to clean up, streamline, and fix the "flow" of the current spec. In particular:

   • I've moved the copy of the "yanking" PEP to its own page with proper linking, and made it consistent with how the other amending PEPs are documented (field changes are noted under the HTML and JSON sections with links to the separate page for full semantics)
   • I've moved some of the more "mechanical" parts of the living spec (about normalized names, API versioning, etc.) to the top of the page, since it was previously awkward to not have their concepts introduced until halfway through the page (at which point they're already being used)
   • I've tweaked the layout/headings slightly on the HTML sections, so that they more closely mirror the JSON sections in terms of clearly distinguishing between the "top" and "detail" indices.
   • Finally I've gone throughout and bumped the examples to API version 1.4, since that's what PEP 792 was approved with.

All changes besides the ones approved with PEP 792 should be non-semantic, i.e. they should only make the spec easier to read, not change any pre-existing behaviors.

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📚 Documentation preview 📚: https://python-packaging-user-guide--1879.org.readthedocs.build/en/1879/

[woodruffw]

NB: Linkcheck is failing elsewhere:

(guides/installing-scientific-packages: line   19) broken    https://math-atlas.sourceforge.net/ - 403 Client Error: Forbidden for url: https://math-atlas.sourceforge.net/

[woodruffw]

CCing @webknjaz and @ncoghlan for review, if either you have the time 🙂

[ncoghlan]

Change looks good to me. One minor tweak to the inline history suggested.

https://math-atlas.sourceforge.net/ is resolving for me now, so it's plausible it was just a glitch and rerunning CI (which will happen automatically if the suggestion is accepted) may make the error go away.

[woodruffw]

Looks like the link is fixed, but a different anchor is now broken. I'll fix that...

[woodruffw]

Nope, still broken:

(guides/installing-scientific-packages: line   19) broken    https://math-atlas.sourceforge.net/ - 403 Client Error: Forbidden for url: https://math-atlas.sourceforge.net/

That page loads correctly for me in my browser, so it's presumably a UA or IP blocking thing.

[ncoghlan]

@woodruffw Offending links are ignored on main now, but I'm not seeing the "update branch" button in the web UI, so you appear to be the one that needs to push that.

[woodruffw]

@woodruffw Offending links are ignored on main now, but I'm not seeing the "update branch" button in the web UI, so you appear to be the one that needs to push that.

Ah yeah, that's because my PR is from an org fork rather than a user fork, and GitHub has never fixed that bug. Sorry for the confusion, just updated!