Rollup merge of rust-lang#23363 - meqif:master, r=alexcrichton

 There was a minor typo in the book's concurrency section (\"recieve\" instead of \"receive\").

Author: Manishearth

src/doc/trpl/concurrency.md

@@ -339,7 +339,7 @@ fn main() {
         });
     }
 
-   rx.recv().ok().expect("Could not recieve answer");
+   rx.recv().ok().expect("Could not receive answer");
 }
 ```