Rollup merge of #32373 - tclfs:patch-5, r=steveklabnik
Rollup merge of #32373 - tclfs:patch-5, r=steveklabnik

docs: Correct an  improper description

In the example, we made a immutable borrow to `println!`, not a mutable one.

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