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

rustc-dev-guide subtree update

Subtree update of `rustc-dev-guide` to https://github.com/rust-lang/rustc-dev-guide/commit/1263fc23672325c1d2e3d6bba8a7dd89e986245c.

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

r? ``@ghost``