Rollup of 10 pull requests

[matthiaskrgr]

Successful merges:

• Migrating rustc_infer to session diagnostics (part 4) #107034 (Migrating rustc_infer to session diagnostics (part 4))
• Fix unintentional UB in ui tests #107972 (Fix unintentional UB in ui tests)
• Make InferCtxt::can_eq and InferCtxt::can_sub return booleans #108010 (Make InferCtxt::can_eq and InferCtxt::can_sub return booleans)
• make x look for x.py if shell script does not exist #108021 (make x look for x.py if shell script does not exist)
• Use target instead of machine for mir interpreter integer handling. #108047 (Use target instead of machine for mir interpreter integer handling.)
• Don't suggest #[doc(hidden)] trait methods with matching return type #108049 (Don't suggest #[doc(hidden)] trait methods with matching return type)
• Better names for illegal impl trait positions #108066 (Better names for illegal impl trait positions)
• rustdoc: Use more let chain #108076 (rustdoc: Use more let chain)
• clarify correctness of black_box #108088 (clarify correctness of black_box)
• Demonstrate I/O in File examples #108094 (Demonstrate I/O in File examples)

Failed merges:

r? @ghost
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