Remove unnecessary `impl Clean<String> for InternedString`.
Remove unnecessary `impl Clean<String> for InternedString`.

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