Auto merge of #90460 - pietroalbini:bidi-stable, r=nikomatsakis,pietroalbini
[stable] Fix CVE-2021-42574 and prepare Rust 1.56.1
This PR implements new lints to mitigate the impact of [CVE-2021-42574], caused by the presence of bidirectional-override Unicode codepoints in the compiled source code. [See the advisory][advisory] for more information about the vulnerability.
The changes in this PR will be released later today as part of Rust 1.56.1.
[CVE-2021-42574]: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-42574
[advisory]: https://blog.rust-lang.org/2021/11/01/cve-2021-42574.html
