Auto merge of #64096 - GuillaumeGomez:theme-regex-fix, r=Mark-Simulacrum
Auto merge of #64096 - GuillaumeGomez:theme-regex-fix, r=Mark-Simulacrum

Fix regex replacement in theme detection

Fixes #64061.

This is sadly a lot of bad luck: after making the changes and re-build the docs, I just forgot to force reload the page. Hence having the old (working) version with two replacements instead of the failing regex. Sorry again about that...

cc @fenhl
r? @Mark-Simulacrum

graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust