Rollup merge of #36374 - dangcheng:patch-1, r=steveklabnik
Rollup merge of #36374 - dangcheng:patch-1, r=steveklabnik

book: fix mistake (File::open -> File::create)

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