Investigate outline on cross references in Safari

[pradyunsg]

Furo: 2023.9.10
Sphinx: 7.2.6
Safari: 17.1
macOS: Ventura 13.6.2

Here is a picture of what the documentation of a particular function looks like on Chrome:

On Safari, note that there is a bright blue border around on one of the cross-references:

Here is a link to the project page on readthedocs, which shows this issue as well: https://drjit.readthedocs.io/en/nanobind_v2/reference.html. Curiously, the set of "bubbles" there is actually different from those in my offline build 🤔

Originally posted by @wjakob in #740