Try to enable all webidls (#573)

* Try to enable all webidls

* Separate out unavailable webidl files by reason.

* Create record of fully tested WebIDL files

* Update notes to reflect new situation with web-idl

* Make a blank ident fail, disable the necessary widls.

It turns out that all the blank idents came from blank enum variants,
which is allowed in webidl apparently.

crates/web-sys/webidls/enabled/TreeContentView.webidl

@@ -0,0 +1,20 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+[Func="IsChromeOrXBL"]
+interface TreeContentView
+{
+  /**
+   * Retrieve the content item associated with the specified row.
+   */
+  [Throws]
+  Element? getItemAtIndex(long row);
+
+  /**
+   * Retrieve the index associated with the specified content item.
+   */
+  long getIndexOfItem(Element? item);
+};
+TreeContentView implements TreeView;