Rollup merge of #144905 - tshepang:rdg-sync, r=jieyouxu

rustc-dev-guide subtree update

Subtree update of `rustc-dev-guide` to rust-lang/rustc-dev-guide@1263fc2.

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

r? ``@ghost``

Author: samueltardieu