Rollup merge of #45361 - GuillaumeGomez:fs-docs, r=QuietMisdreavus
Rollup merge of #45361 - GuillaumeGomez:fs-docs, r=QuietMisdreavus

Add missing code examples

r? @rust-lang/docs

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