Auto merge of #137855 - matthiaskrgr:rollup-uh7f3fi, r=matthiaskrgr

Rollup of 10 pull requests

Successful merges:

 - #137804 (rename BackendRepr::Vector → SimdVector)
 - #137807 (Fully qualify `Result` in generated doctest code)
 - #137809 (Use correct error message casing for `io::const_error`s)
 - #137818 (tests: adapt for LLVM 21 changes)
 - #137822 (Update query normalizer docs to not position it as the greatest pioneer in the space of normalization)
 - #137824 (Tweak invalid RTN errors)
 - #137828 (Fix inaccurate `std::intrinsics::simd` documentation)
 - #137830 (Fix link failure on AVR (incompatible ISA error))
 - #137837 (Update `const_conditions` and `explicit_implied_const_bounds` docs)
 - #137840 (triagebot: only ping me for constck)

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

Diff for: crates/hir-ty/src/layout.rs

@@ -192,7 +192,7 @@ fn layout_of_simd_ty(
     Ok(Arc::new(Layout {
         variants: Variants::Single { index: struct_variant_idx() },
         fields,
-        backend_repr: BackendRepr::Vector { element: e_abi, count: e_len },
+        backend_repr: BackendRepr::SimdVector { element: e_abi, count: e_len },
         largest_niche: e_ly.largest_niche,
         uninhabited: false,
         size,