Fix some typos, broken links and other issues in extension docs

chrome/common/extensions/docs/templates/intros/permissions.html

Index: chrome/common/extensions/docs/templates/intros/permissions.html
===================================================================
--- chrome/common/extensions/docs/templates/intros/permissions.html	(revision 181647)
+++ chrome/common/extensions/docs/templates/intros/permissions.html	(working copy)
@@ -58,7 +58,7 @@
 <p>
   Declare optional permissions in your <a href="manifest.html">extension
   manifest</a> with the <code>optional_permissions</code> key, using the
-  same format as the <a href="manifest.html#permissions">permissions</a>
+  same format as the <a href="declare_permissions.html">permissions</a>
   field:
 
 <pre>{
@@ -170,4 +170,4 @@
     // required permissions).
   }
 });
-</pre>
+</pre>