Merge ref 'ec3867107526' from rust-lang/rust

Pull recent changes from https://github.com/rust-lang/rust via Josh.

Upstream ref: ec38671075266e9cee0348701da2e133379e7c6c
Filtered ref: ed8e25574abf50600d9d2fd61eda90708ccce6c2
Upstream diff: rust-lang/rust@3f1552a...ec38671

This merge was created using https://github.com/rust-lang/josh-sync.

Author: The Miri Cronjob Bot

src/tests/intro.md

@@ -70,10 +70,12 @@ package tests:
 
 Tidy is a custom tool used for validating source code style and formatting
 conventions, such as rejecting long lines. There is more information in the
-[section on coding conventions](../conventions.md#formatting).
+[section on coding conventions](../conventions.md#formatting) or the [Tidy Readme].
 
 > Examples: `./x test tidy`
 
+[Tidy Readme]: https://github.com/rust-lang/rust/blob/master/src/tools/tidy/Readme.md
+
 
 ### Formatting