Improve Rust scraper

[cpmsmith]

Several improvements to the Rust scraper here. In screenshots, before is on the left, after is on the right.

Improve broken page names in Rust

As described in #2568:

• all pages in the Rust Reference had .. on the beginning of their title
• many had their title as .. The Rust Reference
• others had their title as the first subheading on the page, but not the main title
• and some in The Book had similar problems

Now, no empty dots, things in the intro of the book all get 00.00. so they're sorted to the top, and pages in the Book and the Reference all get the correct title.

Screenshots

Update to new compiler error codes location

It got moved, and is no longer all on one page.

Screenshot

Fix and style syntax definitions/diagrams in Rust Reference

The Rust Reference has syntax diagrams and definitions for a bunch of things, which were missing styles and elements before, and had a non-functional toggle button. I put them in a working <details> element and adapted SVG styles from the original.

Screenshot

Note

This meant changing the global CleantTextFilter to include some SVG elements if they're empty. This affects all the docs, but I think in a mostly positive way. For instance, the Web APIs docs have some broken SVGs in them for this same reason:

Screenshot

…however, I haven't verified that this will improve this exact case, because the MDN scraper appears to be broken at the moment. (It's broken on main as well)

I also made some modifications to the global link handling, because:

1. a tags in an SVG don't behave quite like normal ones, so they would break history navigation
2. Unlike native browser navigation, navigating to a fragment inside a closed <details> element didn't open the <details>, and I added a lot of those, so I implemented that.

Remove visible anchor links from Rust Reference

These are hidden in the original docs, and they're all over the place:

Screenshot

[simon04]

Great, thank you!