Auto merge of #50968 - kennytm:rollup, r=kennytm

Auto merge of #50968 - kennytm:rollup, r=kennytm

Rollup of 15 pull requests

Successful merges:

 - #50846 (Add E0665)
 - #50849 (CheckLoopVisitor: also visit closure arguments)
 - #50863 (Make `[T]::len` and `str::len` const fn)
 - #50875 (rustdoc: use "short form" doc(cfg) printing even when combined with other conditionals)
 - #50913 (Fix typo in cell.rs)
 - #50914 (Issue #50636: Improve error diagnostic with missing commas after struct fields.)
 - #50931 (Inline `try_get`.)
 - #50932 (Optimize seen Predicate filtering.)
 - #50945 (Stabilize feature from_ref)
 - #50946 (rustc: Fix procedural macros generating lifetime tokens)
 - #50947 (rustdoc: set tab width in rust source blocks)
 - #50952 (Add the 2018 edition of the book to doc.rust-lang.org)
 - #50958 (Micro-optimization on PR#50697)
 - #50961 (Fix FileCheck finding with MSVC)
 - #50963 (Right-size the `VecDeque` in `coerce_unsized`.)

Failed merges: