Rustdoc: long lines are escaping text code blocks

[WaffleLapkin]

Repro:

/// ```text
/// aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
/// ```
/// ```rust
/// bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
/// ```
pub struct Item;

Rustdoc output:

It seems that only code block with text language are affected.

cc @GuillaumeGomez

Meta

; rustdoc --version --verbose
rustdoc 1.55.0-nightly (240ff4c4a 2021-07-09)
binary: rustdoc
commit-hash: 240ff4c4a0d0936c9eeb783fa9ff5c0507a6ffb4
commit-date: 2021-07-09
host: x86_64-unknown-linux-gnu
release: 1.55.0-nightly
LLVM version: 12.0.1

[WaffleLapkin]

A quick test showed that the bug was introduced in nightly-2021-06-30 (i.e.: nightly-2021-06-29 works fine)

[WaffleLapkin]

@rustbot label +regression-from-stable-to-nightly

[GuillaumeGomez]

Thanks, I'll fix it in the next hours.

[GuillaumeGomez]

In case you want to take a look to the fix, it's #87056.