Rollup of 8 pull requests

[matthiaskrgr]

Successful merges:

• deref patterns: implement implicit deref patterns #138528 (deref patterns: implement implicit deref patterns)
• support config extensions #138934 (support config extensions)
• rustdoc-json: Output target feature information #139393 (rustdoc-json: Output target feature information)
• sync::mpsc: prevent double free on Drop #139553 (sync::mpsc: prevent double free on Drop)
• Remove name_or_empty #139615 (Remove name_or_empty)
• Disable combining LLD with external llvm-config #139853 (Disable combining LLD with external llvm-config)
• rustdoc/clean: Fix lowering of fn params (fixes correctness & HIR vs. middle parity regressions) #139913 (rustdoc/clean: Fix lowering of fn params (fixes correctness & HIR vs. middle parity regressions))
• Ignore aix for tests/ui/erros/pic-linker.rs #139942 (Ignore aix for tests/ui/erros/pic-linker.rs)

r? @ghost
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