Style for the snippet displayed on rustup.rs is slightly broken

[JohnTitor]

Problem

Copy button won't show or work well, and style for the snippet is broken on some environment.

I'm not sure how often is the website updated but I assume that's related to #2326.

It looks like this to me (Incognito Chrome on Windows):

Steps

1. Visit https://rustup.rs.
2. See the command and what's happen.

[kinnison]

Drat, I thought we'd solved all the snafus with that when we merged #2326. Thanks for spotting that.

@BeniCheni do you have time to try the different browsers out and see if you can fix things? If not, I suggest we revert the change to the page until someone can rework whatever went wrong. I'm not an HTML/CSS expert and it looks okay to me on my browser (firefox in Linux) so I'm not sure what to do.

[BeniCheni]

@kinnison, will take a look to either provide a fix or revert. Thanks for informing.

[BeniCheni]

@kinnison et al, tried a fix PR. 🙏

[BeniCheni]

Note: the corrupted style of overflown text has been tested locally by this command in the PR:

#2398 (comment)