Furo

- Improve code block styling.
- Explicitly declare compatibility constraints for pygments.
- Break words in API documentation, when the words are too long.
- Drop the `def ` on function and method signatures.
- Reduce the font-weight in `sig-prename`.

- 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.