Auto merge of #130069 - GuillaumeGomez:gen-scraped-buttons, r=notriddle

Generate scraped examples buttons in JS

Follow-up of rust-lang/rust#129796.

To reduce the page size when there are scraped examples, we can generate their buttons in JS since they require JS to work in any case. There should be no changes in display or in functionality.

You can test it [here](https://rustdoc.crud.net/imperio/gen-scraped-buttons/doc/scrape_examples/fn.test.html).

cc `@willcrichton`
r? `@notriddle`

Author: bors