rollup merge of rust-lang#19608: jbranchaud/add-missing-semicolon-in-intro

Author: alexcrichton

src/doc/intro.md

@@ -64,7 +64,7 @@ Here's what's in `src/main.rs`:
 
 ```{rust}
 fn main() {
-    println!("Hello, world!")
+    println!("Hello, world!");
 }
 ```