Add a b'x' byte literal of type u8.

src/libsyntax/print/pprust.rs

@@ -2305,6 +2305,12 @@ impl<'a> State<'a> {
         }
         match lit.node {
             ast::LitStr(ref st, style) => self.print_string(st.get(), style),
+            ast::LitByte(byte) => {
+                let mut res = String::from_str("b'");
+                (byte as char).escape_default(|c| res.push_char(c));
+                res.push_char('\'');
+                word(&mut self.s, res.as_slice())
+            }
             ast::LitChar(ch) => {
                 let mut res = String::from_str("'");
                 ch.escape_default(|c| res.push_char(c));