[rustdoc] Add copy code feature
This PR adds a "copy code" to code blocks. Since this is a JS only feature, the HTML is generated with JS when the user hovers the code block to prevent generating DOM unless needed.
Two things to note:
1. I voluntarily kept the current behaviour of the run button (only when hovering a code block with a mouse) so it doesn't do anything on mobile. I plan to send a follow-up where the buttons would "expandable" or something. Still need to think which approach would be the best.
2. I used a picture and not text like the run button to remain consistent with the "copy path" button. I'd also prefer for the run button to use a picture (like what is used in mdbook) but again, that's something to be discussed later on.
The rendering looks like this:
It can be tested [here](https://guillaume-gomez.fr/rustdoc/bar/struct.Bar.html) (without the run button) and [here](https://guillaume-gomez.fr/rustdoc/foo/struct.Bar.html) (with the run button).
Fixes#86851.
r? ``@notriddle``
rustdoc: dedup search form HTML
This change constructs the search form HTML using JavaScript, instead of plain HTML. It uses a custom element because
- the [parser]'s insert algorithm runs the connected callback synchronously, so we won't get layout jank
- it requires very little HTML, so it's a real win in size
[parser]: https://html.spec.whatwg.org/multipage/parsing.html#create-an-element-for-the-token
This shrinks the standard library by about 60MiB, by my test.
There should be no visible changes. Just use less disk space.
This change constructs the search form HTML using JavaScript, instead of plain HTML. It uses a custom element because
- the [parser]'s insert algorithm runs the connected callback synchronously, so we won't get layout jank
- it requires very little HTML, so it's a real win in size
[parser]: https://html.spec.whatwg.org/multipage/parsing.html#create-an-element-for-the-token
This shrinks the standard library by about 60MiB, by my test.
Move duplicated code in functions in `tests/rustdoc-gui/notable-trait.goml`
It also allowed me to add some new common test like:
```
assert-position: (
"//*[`@class='tooltip` popover']",
{"x": |popover_x|}
)
```
r? `@notriddle`
