Bring back the visual difference between sig-prename and sig-name

[viktorasm]

If you check latest docs for urllib3, you can see that class module and class name is rendered differently, e.g.:

https://urllib3.readthedocs.io/en/stable/reference/urllib3.util.html#urllib3.util.SSLContext

When trying this with latest version 2021.11.16, both package and classname is rendered visually the same. I guess the previous behavior was the intended behavior, and it would be nice to retain this. For now reverting my builds to version 2021.09.22 (as used by urllib3 at the time of this post)

[viktorasm]

Did more testing and it seems like this got introduced in 2021.11.15. Checking the diff with the previous release shows that there were changes on .sig styling:

2021.11.12.1...2021.11.15

[viktorasm]

as a hack, added a simple override directly in documentation. Tried various options to differentiate from the name, going with bold+param color seemed to look best:

.sig .sig-prename {
    color:  rgb(90, 92, 99);
}

[pradyunsg]

Done in 782574e