Rollup of 26 pull requests

[arielb1]

• Successful merges: Point to enclosing block/fn on nested unsafe #39202, Export attributes in save-analysis data #39820, Fix suggestion span error with a line containing multibyte characters #40092, Better docs of rusty parts of typeck #40146, rustbuild: Build documentation for proc_macro #40199, Restore creating the channel-rust-$channel-date.txt files #40225, Remove ability for plugins to register a MIR pass #40239, Fix emscripten test detection #40259, Clean up rustdoc css #40278, Fix incorrect span label formatting #40287, Expect macro defs in save-analysis and add expn info to spans for att… #40311, Allow lints to check Bodys directly #40315, Disallow subtyping between T and U in T: Unsize<U>. #40319, Update syntax for pub(restricted) #40340, save-analysis: cope with lack of method data after a type error #40344, Fix missing backtick typo #40345, Do not bother creating StorageLive for TyNever #40372, Fix UB in repr(packed) tests #40373, Box docs: no allocation is done for ZSTs. #40379, emit !align attributes on stores of operand pairs #40385, Distinguish the ways CStr::from_bytes_with_nul can fail #40386, Implement placement-in protocol for VecDeque #40389, Update gdbr tests #40400, fix #40294 obligation cause.body_id is not always a NodeExpr #40404, OsString::shrink_to_fit. #40410, Clarify docs in VecDeque::resize #40423
• Failed merges:

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