Docs inline viewer infrastructure

[jprochazk]

Snippets™️ (formerly known as "code examples" or "doc examples") are now built on CI together with Examples™️, and uploaded to the same place.

Also includes some changes to example screenshots (adding data-inline-viewer attributes), and updating the egui rev to fix a bug

• Blocked by Fix crash on request_animation_frame when destroying web runner emilk/egui#4169

Checklist

• I have read and agree to Contributor Guide and the Code of Conduct
• I've included a screenshot or gif (if applicable)
• I have tested the web demo (if applicable):
  • Using newly built examples: app.rerun.io
  • Using examples from latest main build: app.rerun.io
  • Using full set of examples from nightly build: app.rerun.io
• The PR title and labels are set such as to maximize their usefulness for the next release's CHANGELOG
• If applicable, add a new check to the release checklist!

• PR Build Summary
• Docs preview
• Examples preview
• Recent benchmark results
• Wasm size tracking

[github-actions]

Size changes

Name	main	5438/merge	Change
arkit_scenes.rrd	39.43 MiB	40.34 MiB	+2.31%

[jprochazk]

I did all the renaming in 521415f and onward (though there are some mentions of "snippet" mixed in the earlier commits). Hopefully it's a bit easier to review this way.

[emilk]

Looks good, except the double panic hook

It would have been easier to review if the "code-example -> snippet" renaming had come in its own PR though

[emilk]

giving complex expressions a name can greatly improve readability

Suggested change

	if !path.extension().is_some_and(|p| p == "py") {
	let has_python_extension = path.extension().is_some_and(|p| p == "py");
	if !has_python_extension {

[jprochazk]

I think this one is already pretty readable, putting it into a variable feels like I'm repeating myself

[jprochazk]

It would have been easier to review if the "code-example -> snippet" renaming had come in its own PR though

I just wanted to get it over with, because after this PR we would have:

• Code example
• Doc example
• Snippet

All mean the same thing.