Support paren vs. dot for ordered list markers per CommonMark specification.

lib/rules.js

@@ -625,7 +625,7 @@ module.exports = [
         if (!list.unordered) {
           var number = 1;
           list.items.forEach(function forItem(item) {
-            var re = new RegExp("^[\\s>]*" + String(number) + "\\.");
+            var re = new RegExp("^[\\s>]*" + String(number) + "[\\.)]");
             if (!re.test(item.line)) {
               errors.push(item.lineNumber);
             }

test/ordered_list_item_prefix-paren.md

@@ -0,0 +1,13 @@
+Good list:
+
+1) Do this.
+1) Do that.
+1) ???
+1) Profit!
+
+Bad list:
+
+1) Do this.
+2) Do nothing. {MD029}
+3) ??? {MD029}
+4) Failed! {MD029}

test/ordered_list_item_prefix_ordered-paren.json

@@ -0,0 +1,6 @@
+{
+  "default": true,
+  "MD029": {
+    "style": "ordered"
+  }
+}

test/ordered_list_item_prefix_ordered-paren.md

@@ -0,0 +1,13 @@
+Good list:
+
+1) Do this.
+2) Do that.
+3) ???
+4) Profit!
+
+Bad list:
+
+1) Do this.
+1) Do nothing. {MD029}
+1) ??? {MD029}
+1) Failed! {MD029}