rustdoc bug rendering constant section

[frewsxcv]

https://api.rocket.rs/rocket/http/struct.ContentType.html

cc @GuillaumeGomez @SergioBenitez

[clarfonthey]

May be related: on the latest nightly I'm noticing that double quotes are no longer escaped on implementors/**.js. However, I'm noticing that on master they appear to be escaped. Perhaps something changed recently?

[ollie27]

@clarcharr that was indeed also triggered by #39944, I've submitted a fix for that: #40451.