Co-authored-by: the8472 <the8472@users.noreply.github.com>

Now that we record the crate's name in its `clean::Item`, pushing the
crate name onto the `stack` causes duplicate paths. E.g., the URL
generated for the path `::foo::bar::baz` would be something like

    ../foo/foo/bar/baz

With this commit, the URL is corrected to

    ../foo/bar/baz

I'm wondering if it was originally there so that we could `take` the
module which enables `after_krate` to take an `&Crate`. However, the two
impls of `after_krate` only use `Crate.name`, so we can pass just the
name instead.

The previous changes mean that we can now remove this `Option`.

…order, r=CraftSpider,jyn514

Sidebar trait items order

We were actually sorting `Symbol` and not `String`, creating a completely invalid sort result. I added a test to prevent regressions.

r? ``@jyn514``

Only enable assert_dep_graph when query-dep-graph is enabled.

This is a debugging option. The only effect should be on rustc tests.

r? ``@michaelwoerister``

Add internal io::Error::new_const to avoid allocations.

This makes it possible to have a io::Error containing a message with zero allocations, and uses that everywhere to avoid the *three* allocations involved in `io::Error::new(kind, "message")`.

The function signature isn't perfect, because it needs a reference to the `&str`. So for now, this is just a `pub(crate)` function. Later, we'll be able to use `fn new_const<MSG: &'static str>(kind: ErrorKind)` to make that a bit better. (Then we'll also be able to use some ZST trickery if that would result in more efficient code.)

See rust-lang#83352

Allow not emitting `uwtable` on Android

`uwtable` is marked as required on Android, so it can't be disabled via `-C force-unwind-tables=no`. However, I found that the reason it's marked as required was to resolve a [backtrace issue in Gecko](rust-lang#49867), and I haven't find any other reasons that make it required ([yet](https://rust-lang.zulipchat.com/#narrow/stream/122651-general/topic/Unwind.20tables.20are.20strictly.20required.20on.20Windows.20and.20Android)). Therefore, I assume it's safe to turn it off if a (nice) backtrace is not needed, and submit this PR to allow `-C force-unwind-tables=no` when targeting Android.

Note that I haven't tested this change on Android as I don't have an Android environment for testing.

Change `-W help` to display edition level.

`-W help` was not honoring the `--edition` flag when displaying the default lint level. It was using the edition for sorting, but not for the final display.

This isn't important right now as there aren't any edition-specific lint levels. Also, the `declare_lint` macro is broken and doesn't even allow setting them right now. However, I figure it wouldn't hurt to fix this before I forget about it, in case edition-specific lints are ever used in the future.

…sition, r=Nemo157

Codeblock tooltip position

The codeblocks tooltips were misplaced. Normally, there is no top margin applied to a tooltip unless the codeblock is the first element of the doc block. The CSS rule was too vague though, applying it to all tooltips where the codeblock was the first child of its parent. Which can be easily seen with lists:

Before:

![Screenshot from 2021-03-22 22-05-16](https://user-images.githubusercontent.com/3050060/112059812-a667ba80-8b5c-11eb-88dd-1c598ceb3766.png)

After:

![Screenshot from 2021-03-22 22-06-31](https://user-images.githubusercontent.com/3050060/112059815-a7005100-8b5c-11eb-9e40-8fc57513e498.png)

r? ``@Nemo157``

…e, r=jyn514

rustdoc: Record crate name instead of using `None`

Fixes rust-lang#83365.

r? `@jyn514`

…aumeGomez

Slight visual improvements to warning boxes in the docs

First I noticed that sometimes the thumbs-down emoji in the docs is hard to see and hard to look at because the yellow emoji color and the color of the box below are so bright. Especially if you look at the screen late at night you can notice it. I thought I should change that so I added a black outline around the emoji. It works using the [`text-shadow`](https://developer.mozilla.org/en-US/docs/Web/CSS/text-shadow) property. It may be a bit hacky but it seems to work well and browser compatibility looks pretty good too: [browser compatibility](https://developer.mozilla.org/en-US/docs/Web/CSS/text-shadow#browser_compatibility).
For consistency the microscope has the black border too.
Alternatively I had `drop-shadow(0px 0px 1px black);` in mind but its [browser compatibility](https://developer.mozilla.org/en-US/docs/Web/CSS/filter-function/drop-shadow()#browser_compatibility) doesn't look as good and the blurry shadow probably doesn't look as good either.

Then, I thought that now that I'm at it I could also try changing the purple color to a color you would rather expect to see for deprecation: red. For the red I've taken the blue and reused it as a foundation and moved it to the red color spectrum.
But then I thought that the purple color could still be reused for something else: for the boxes that tell you about portability (e.g. _only supported on Unix_). These are currently blue.

I think blue doesn't really represent danger like it should. Not being cross-platform represents a danger because if you want to compile for a different platform, your code may not compile anymore. Blue looks too friendly and is in my opinion more suitable for a box containing general information like for instance "This is available since 1.0.0". None of the current three box types (unstable, deprecated and portability) are that.

I think purple is a better fit for it because it's kind of in the middle between "use it" and "don't use it". Deprecated is definitely "don't use it". To illustrate this better, here's a color spectrum:

Blue = friendly,  "use it".
![image](https://user-images.githubusercontent.com/35064754/112139891-9a6b0f80-8bd3-11eb-94e1-dc747a3d4cf9.png)
Red = danger, "don't use it".

And the purple in the middle (the color that the portability box now has) probably represents "use it if you have to", so it's not entirely friendly and not entirely a danger. That is why I think it fits.

However I made one change to that existing purple: I made the outer color a bit brighter because it's outstandingly dark compared to the other outer colors of the other boxes.

This is all subjective but in my opinion it looks nicer. At first you might need to get used to it though. Notice the box colors and the black outlines around the emoji shapes:
![image](https://user-images.githubusercontent.com/35064754/112139327-ebc6cf00-8bd2-11eb-88ac-25219b43a1a0.png)
![image](https://user-images.githubusercontent.com/35064754/112139392-000acc00-8bd3-11eb-90c2-81feec93c521.png)

… r=jyn514

Remove unnecessary `Option` wrapping around `Crate.module`

I'm wondering if it was originally there so that we could `take` the
module which enables `after_krate` to take an `&Crate`. However, the two
impls of `after_krate` only use `Crate.name`, so we can pass just the
name instead.