Piccolo-theme

Improved the colours used for syntax highlighting whilst in dark mode (one of the blue colours was too dark). Thanks to superstes for reporting this issue.

Fixing some style issues in the search results page in Sphinx 7.3.x.

Fixed a styling issue with the search box in Sphinx 7.3.x. Thanks to heuer for reporting this issue.

Allow [parallel builds](https://www.sphinx-doc.org/en/master/man/sphinx-build.html#cmdoption-sphinx-build-j).

Thanks to explode for reporting this issue.

Added additional ordered list styles - thanks to fizbin for reporting this.

Fixed span tags (thanks to jvcarli for this).

Added support for Python 3.12.