Auto merge of #38105 - ollie27:rustdoc_deterministic_js, r=GuillaumeGomez
Auto merge of #38105 - ollie27:rustdoc_deterministic_js, r=GuillaumeGomez

rustdoc: Sort lines in search index and implementors js

This means the files are generated deterministically even with rustdoc running in parallel.

Fixes the first part of #30220.

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