Fix typo in "Loops" section of the book
Fix typo in "Loops" section of the book

Closes #31195
graydon/rust,GBGamer/rust,graydon/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,aidancully/rust,aidancully/rust,GBGamer/rust,GBGamer/rust,graydon/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,GBGamer/rust,aidancully/rust