Better anchor support

[MahdiBM]

Is your feature request related to a problem? Please describe

Anchors are not shown where they should.

Describe the solution you'd like

https://www.swift.org/documentation/server/guides/libraries/log-levels.html
I'd like to be able to share a link pointing to a specific part of the page, like Structured Logging (Semantic Logging).

Describe alternatives you've considered

Additional context

[MahdiBM]

Looks like only ##s (and perhaps #s) get the anchor.
At least ### should also have an anchor, possibly ####s as well.

[madrob]

If you inspect source, ### already has an id attribute so it could have an anchor link, but the 🔗 glyph just doesn't show up on mouseover. So the direct link to that section would be https://www.swift.org/documentation/server/guides/libraries/log-levels.html#structured-logging-semantic-logging

Would love to see this improved on the page, though.