Furomon

- Fix a typo, that broke the sidebar highlight logic.

- Tweak API documentation presentation to match pdoc3's style.
- Bring back browser-specific prefixes, for compatibility.

- Fix RECORD file contents.

- Adopt `sphinx-theme-builder`, which runs the JS-based asset build process during the regular Python build process.
- Rework the build pipeline to be webpack-based.
- Tweak colours in dark mode.
- Present better error messages on misconfiguration.
- Tweak presentation of blockquotes, to be more visually distinct.
- Stylize topics like admonitions, as specified in the reStructuredText spec.
- Handle long single words in the sidebar.
- Only hide Sphinx from the footer, when `show_sphinx` is set to `False`.

- Add a bit more space below content icon container.
- Add CSS variables for table header background and table border.
- Fix behaviour of URL-style references in `html_logo` and `html_favicon`.
- Improve selector for embedded-in-text images.
- Improve the contrast ratios in API documentation.

- Restyle API documentation signatures, to have a background and use monospace fonts.
- Reduce spacing for items in API documentation.
- Improve the presentation of links in site-wide announcement.
- Only add a border on code inside paragraphs.
- Use `noscript` for presenting "search needs JS" message.