Rollup merge of #65444 - spastorino:as-ref-for-list, r=Mark-Simulacrum
Rollup merge of #65444 - spastorino:as-ref-for-list, r=Mark-Simulacrum

Implement AsRef<[T]> for List<T>

r? @Mark-Simulacrum

aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust