Improve display of clippy lints page when JS is disabled

[GuillaumeGomez]

There is no point in displaying the settings menu and the filters if JS is disabled. So in this case, this PR simply hides it:

For the theme handling though, I need to send a fix to mdBook first. But once done, it'll look as expected (dark if system is in dark mode).

changelog: Improve clippy lints page display when JS is disabled.

r? @Alexendoo

[flip1995]

2 things I also noticed with the new page:

1. The link button doesn't work for me anymore (latest firefox)

2. The indentation of code blocks is broken/removed: https://rust-lang.github.io/rust-clippy/master/index.html#/cast_possible_truncation

[flip1995]

Also the link https://rust-lang.github.io/rust-clippy/master/index.html#cast_possible_truncation doesn't filter the lint list anymore (with or w/o / after the #), nor does it automatically expand the tab of the lint (no / after the #).

[GuillaumeGomez]

Doesn't come from this PR, things are currently broken it seems. Urg. I'll add GUI tests after all fixes have been sent to prevent this situation from happening again.

Sending fix for the current page shortly.

[GuillaumeGomez]

All mentioned bugs were fixed. This PR can be reviewed now. :)

[Alexendoo]

Let's leave some kind of message to say the filtering requires JS

[GuillaumeGomez]

Good idea!

[GuillaumeGomez]

Added a CSS class on HTML with JS, removed the new CSS file and added back a message in case JS is disabled.

[Alexendoo]

👍

@bors r+

[bors]

📌 Commit ac764df has been approved by Alexendoo

It is now in the queue for this repository.

[bors]

⌛ Testing commit ac764df with merge 52b8324...

[bors]

☀️ Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test
Approved by: Alexendoo
Pushing 52b8324 to master...