Rollup merge of #137804 - RalfJung:backend-repr-simd-vector, r=workingjubilee

rename BackendRepr::Vector → SimdVector

For many Rustaceans, "vector" does not imply "SIMD", so let's be more clear in this type that is used pervasively in the compiler.

r? `@workingjubilee`

Author: matthiaskrgr

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,