Create mod.rs files for the dom and dom::bindings modules.

This gives us a better place to put DOM documentation, which I'd like to start
adding.

components/script/dom/bindings/mod.rs

@@ -0,0 +1,34 @@
+/* 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/. */
+
+//! The code to expose the DOM to JavaScript through IDL bindings.
+
+#![allow(unsafe_blocks)]
+#![deny(missing_docs, non_snake_case)]
+
+pub mod cell;
+pub mod global;
+pub mod js;
+pub mod refcounted;
+pub mod utils;
+pub mod callback;
+pub mod error;
+pub mod conversions;
+pub mod proxyhandler;
+pub mod str;
+pub mod structuredclone;
+pub mod trace;
+
+/// Generated JS-Rust bindings.
+#[allow(missing_docs, non_snake_case)]
+pub mod codegen {
+    #[allow(unrooted_must_root)]
+    pub mod Bindings;
+    pub mod InterfaceTypes;
+    pub mod InheritTypes;
+    pub mod PrototypeList;
+    pub mod RegisterBindings;
+    pub mod UnionTypes;
+}
+