tools,doc: fix incomplete json produced by doctool

Doc tool produces incomplete json when it meets unordered lists that
directly following a heading. Add a default case to processList function
to handle the lists.

PR-URL: https://github.com/nodejs/node/pull/5966
Fixes: https://github.com/nodejs/node/issues/1545
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Robert Lindstädt <robert.lindstaedt@gmail.com>
Reviewed-By: Roman Reiss <me@silverwind.io>

tools/doc/json.js

@@ -260,6 +260,14 @@ function processList(section) {
       // event: each item is an argument.
       section.params = values;
       break;
+
+    default:
+      if (section.list.length > 0) {
+        section.desc = section.desc || [];
+        for (var i = 0; i < section.list.length; i++) {
+          section.desc.push(section.list[i]);
+        }
+      }
   }
 
   // section.listParsed = values;