to better describe the situation

This makes a few code cleanups to follow up on the review comments in
rust-lang#65576.

…ckend.

…e been modified.

…doc, r=ehuss

Target-feature documented as unsafe

@nikomatsakis asked me to help out on the docs on this issue: rust-lang#63597

The following docs have been modified
- ```rustc -C help``` text for `target-feature`
- RustC book:

## Preview of src/doc/rustc/src/targets/index.md
![Screenshot 2019-09-17 at 12 22 45](https://user-images.githubusercontent.com/13764830/65033746-f7826700-d945-11e9-9dd2-d8f9b08f45de.png)

## Preview of src/doc/rustc/src/targets/known-issues.md
![Screenshot 2019-09-17 at 12 22 25](https://user-images.githubusercontent.com/13764830/65033774-00733880-d946-11e9-9398-90f01f3938d5.png)

Fixes rust-lang#63597

Mention keyword closing policy

closes rust-lang#59233 / rust-lang#59233 (comment)

rewording suggestions welcome

> Also in the referenced issue, the commit number of the new commit
> that could close that issue is not really informative. The PR number itself appeared in the issue
> is more informative and concise.

@lzutao what do you mean with that? Is this fixed by the new "May be fixed by #XXXXX"?

…komatsakis

Add more coherence tests

I've wrote the missing test cases listed in [this google doc](https://docs.google.com/spreadsheets/d/1WlroTEXE6qxxGvEOhICkUpqguYZP9YOZEvnmEtSNtM0/edit#gid=0)

> The other thing that might be useful is to rename the existing tests so they all fit the new naming scheme we were using.

I'm not entirely sure how to do this. If everything from the google sheet is covered could I just remove the remaining tests in `src/test/ui/coherence` or is there something in there that should remain?

cc rust-lang#63599

r? @nikomatsakis

Fix test style in unused parentheses lint test

I think this fixes rust-lang#63237
I'm not sure if I had to add text after the `//~ ERROR` comments.
This is my first pull request, so I'm open to feedback.
This issues already received one pull request [here](rust-lang#63257) but it was marked as closed for inactivity.

r?  @nikomatsakis

…-E0588, r=Dylan-DPC

Add long error explanation for E0588

Part of rust-lang#61137.

r? @kinnison

Fix WASI sleep impl

Closes rust-lang#65607

@sunfishcode
Is it fine to use 0 for the `identifier` field? What is this field used for?

…cut, r=Dylan-DPC

Add option to disable keyboard shortcuts in docs

Fixes rust-lang#65211.

r? @Manishearth

…GuilliaumeGomez

Add long error explanation for E0728

Part of rust-lang#61137

r? @GuillaumeGomez

Code cleanups following up on rust-lang#65576.

This makes a few code cleanups to follow up on the review comments in
rust-lang#65576.

r? @Centril

refactor and move `maybe_append`

Add some tests for fixed ICEs

Fixes rust-lang#41366 from 1.35.0
Fixes rust-lang#51431 from 1.31.0-nightly (77af314 2018-10-11) (on my local)
Fixes rust-lang#52437 from nightly
Fixes rust-lang#63496 from nightly

r? @Centril

bring back some Debug instances for Miri

These were erroneously removed in rust-lang#65647, but Miri needs them.

r? @Centril Cc @nnethercote @oli-obk

…-work-item-event-names, r=wesleywiser

self-profiling: Remove module names from some event-ids in codegen backend.

Event-IDs are not supposed to contain argument values. Event-IDs are the equivalent of function names. Proper support for parameters will be added to self-profiling down the line.

This PR fixes an oversight from rust-lang#64840.

r? @wesleywiser

…mulacrum

Add missing space in librustdoc

It just hurts my eyes...

r? @Centril