Add ifs_as_logical_ops lint

[ada4a]

This PR supersedes #14904. All the content is kept the same, apart from some small changes:

• removed the accidentally committed .DS_Store directory (Add ifs_as_logical_ops lint  #14904 (review))
• updated the rustc version (Add ifs_as_logical_ops lint  #14904 (comment))
• restored the is_from_proc_macro check (Add ifs_as_logical_ops lint  #14904 (comment))
• restored the comment in hir_utils.rs accidentally removed in the dogfooding commit

The original description follows:

Fixes #14865 by adding the ifs_as_logical_ops lint.

Only adds the conjunctive version (transform if x else y => x && y) for now.

changelog: [ifs_as_logical_ops] : "Warn about cases where x && y could be used in place of if conditions"

[rustbot]

Thanks for the pull request. A reviewer will take a look after it receives 2 community reviews.

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[ada4a]

The original PR was reviewed to bits already, so going through community review yet again might be superfluous. Let me assign a reviewer, and see what they think.

r? clippy

[github-actions]

Lintcheck changes for 5ee07f1

Lint	Added	Removed	Changed
clippy::ifs_as_logical_ops	5	0	0

This comment will be updated if you push new changes