Rollup merge of #31537 - ollie27:book_doc_example, r=steveklabnik
Rollup merge of #31537 - ollie27:book_doc_example, r=steveklabnik

The code sections shouldn't be inside a ```text block.

r? @steveklabnik

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