Add regression test for #84.

Author: BurntSushi

regex_syntax/src/parser.rs

@@ -1429,6 +1429,15 @@ mod tests {
         });
     }
 
+    #[test]
+    fn error_repeat_beginning_counted() {
+        assert_eq!(perr("{5}"), Error {
+            pos: 0,
+            surround: "{5}".into(),
+            kind: ErrorKind::RepeaterExpectsExpr,
+        });
+    }
+
     #[test]
     fn error_repeat_illegal_exprs_simple() {
         assert_eq!(perr("a**"), Error {