rustdoc: Ayu syntax highlighting regression

[camelid]

My guess is that the yellow inline code style is incorrectly being applied to code blocks too.

Nightly (incorrect)

Beta & stable (correct)

[camelid]

cc @GuillaumeGomez since you're knowledgeable about rustdoc's CSS

[GuillaumeGomez]

I'll send a fix shortly.

[camelid]

#88093 looks to be the likely cause.

searched nightlies: from nightly-2021-07-01 to nightly-2021-08-25
regressed nightly: nightly-2021-08-20
searched commits: from 3d0774d to 6d64f7f
regressed commit: 6d64f7f

bisected with cargo-bisect-rustc v0.6.0

Host triple: x86_64-apple-darwin
Reproduce with:

cargo bisect-rustc --start=2021-07-01 --end=2021-08-25 --preserve --prompt -- doc --open