Rollup merge of #148268 - notriddle:emit-scraped-examples, r=GuillaumeGomez

rustdoc: fix `--emit=dep-info` on scraped examples

Makes sure both stages (the scraping process itself, and the doc build) emit complete dependency lists.

CC rust-lang/rust#146220
Part of rust-lang/rust#83784

Author: GuillaumeGomez