Add migration to WebAssembly information to PNaCl / NaCl docs.

native_client_sdk/doc_generated/devguide/index.html

Index: native_client_sdk/doc_generated/devguide/index.html
diff --git a/native_client_sdk/doc_generated/devguide/index.html b/native_client_sdk/doc_generated/devguide/index.html
index ad96c729487bcbdd13560eb224a4d32021cdbf80..39603d2971435f121b55eff7477391518bc2e704 100644
--- a/native_client_sdk/doc_generated/devguide/index.html
+++ b/native_client_sdk/doc_generated/devguide/index.html
@@ -1,7 +1,15 @@
 {{+bindTo:partials.standard_nacl_article}}
 
-<section id="developer-s-guide">
-<span id="devguide-index"></span><h1 id="developer-s-guide"><span id="devguide-index"></span>Developer&#8217;s Guide</h1>
+<b><font color="#cc0000">
+NOTE:
+Deprecation of the technologies described here has been announced
+for platforms other than ChromeOS.<br/>
+Please visit our
+<a href="/native-client/migration">migration guide</a>
+for details.
+</font></b>
+<hr/><section id="developer-s-guide">
+<h1 id="developer-s-guide">Developer&#8217;s Guide</h1>
 <p>The Native Client Developer&#8217;s Guide includes practical information you need to
 get your development cycle up and running (e.g., how to compile and test-run
 your application), as well as important concepts you need to understand in order