Rollup merge of #161343 - tshepang:rdg-sync, r=tshepang

rustc-dev-guide subtree update

Subtree update of `rustc-dev-guide` to https://github.com/rust-lang/rustc-dev-guide/commit/5613bfeefcb3a250daecd54610cb27fcf69b4884.

Created using https://github.com/rust-lang/josh-sync.

r? @ghost