repr: emit closing `)` for enum variants, test that nullary variants names print

src/libcore/repr.rs

@@ -508,7 +508,7 @@ fn visit_leave_enum_variant(_variant: uint,
                                 _disr_val: int,
                                 n_fields: uint,
                                 _name: &str) -> bool {
-        if !self.printer.skip && n_fields > 1 {
+        if !self.printer.skip && n_fields >= 1 {
             self.printer.writer.write_char(')');
         }
         true

src/test/run-pass/log-knows-the-names-of-variants.rs

@@ -4,8 +4,13 @@ enum foo {
   c,
 }
 
+enum bar {
+  d, e, f
+}
+
 fn main() {
     assert ~"a(22)" == fmt!("%?", a(22u));
     assert ~"b(~\"hi\")" == fmt!("%?", b(~"hi"));
     assert ~"c" == fmt!("%?", c);
+    assert ~"d" == fmt!("%?", d);
 }