Editorial: update the standard for the WHATWG move

[domenic]

• Update repository files using whatwg/spec-factory.
• Use the WHATWG template.
• Add an Acknowledgments section and IPR statement.
• Sentence-case all headings.
• Add missing example IDs and suppress a warning about "optional" being used in an example.
• Minor fixes to the introductory example to work well with WHATWG styling.
• Fix some invalid HTML, double-"the" typos, and usage of "and/or" disallowed by the linter.
• Reword some disallowed uses of RFC 2119 keywords.

Part of #190. See also https://github.com/whatwg/sg/issues/215.

I'd like editor review and also @annevk review if possible.

---

:boom: Error: 400 Bad Request :boom:

PR Preview failed to build. (Last tried on Oct 18, 2023, 5:54 AM UTC).

More

PR Preview relies on a number of web services to run. There seems to be an issue with the following one: :rotating_light: [CSS Spec Preprocessor](https://api.csswg.org/bikeshed/) - CSS Spec Preprocessor is the web service used to build Bikeshed specs. :link: [Related URL](https://api.csswg.org/bikeshed/?url=https%3A%2F%2Fraw.githubusercontent.com%2Fwhatwg%2Furlpattern%2F13b8b1464ec873dab131332035707adba66a8bb0%2Fspec.bs&md-warning=not%20ready) ``` Error running preprocessor, returned code: 2. FATAL ERROR: Found unmatched text macro [COMMIT-SHA]. Correct the macro, or escape it with a leading backslash. ✘ Did not generate, due to errors exceeding the allowed error level. ``` _If you don't have enough information above to solve the error by yourself (or to understand to which web service the error is related to, if any), please [file an issue](https://github.com/tobie/pr-preview/issues/new?title=Error%20not%20surfaced%20properly&body=See%20whatwg/urlpattern%23193.)._

[domenic]

The build will fail until we run spec-factory to update the Makefile, etc.; that will be a separate pull request. (Which we can merge before this one.)

[annevk]

Running spec-factory would be good because then PR Preview works and we can see what the document ends up looking like, right?

[domenic]

Yeah, I'll try to land that first, but I think that depends on db.json.

[jeremyroman]

Looks fine on inspection, but a preview would be nice. :)

[domenic]

I think a preview is not possible because PR preview is using the old config file against the new spec, or something like that, and thus fails the whole process when it can't generate the old spec in order to create diffs.

In lieu of that I've set up a preview here: https://boom-bath.glitch.me/urlpattern-preview.html

Editor review especially appreciated for changes to spec.bs.

[domenic]

The standard is live! https://urlpattern.spec.whatwg.org/