Rollup merge of #57267 - rust-lang:SimonSapin-patch-1, r=varkor
Rollup merge of #57267 - rust-lang:SimonSapin-patch-1, r=varkor

src/jemalloc is gone, remove its mention from COPYRIGHT

The `src/jemalloc` submodule was removed in 61e89446ef6e115630faa75c985c599d739f7586 / https://github.com/rust-lang/rust/pull/55238.

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