Remove .html extension from links

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

 <p>
 An <code>Event</code> is an object
 that allows you to be notified
 when something interesting happens.
 Here's an example of using the
 <code>chrome.alarms.onAlarm</code> event
 to be notified whenever an alarm has elapsed:
 </p>
 
 <pre>
@@ skipping 20 matching lines @@
 
 Example APIs using Events:
 $(ref:alarms),
 {{?is_apps}}
 $(ref:app.runtime),
 $(ref:app.window),
 {{/is_apps}}
 $(ref:i18n),
 $(ref:identity),
 $(ref:runtime).
-Most <a href="api_index.html">chrome APIs</a> do.
+Most <a href="api_index">chrome APIs</a> do.
 
 {{^is_apps}}
 <div class="doc-family extensions">
 <h2 id="declarative">Declarative Event Handlers</h2>
 
 <p>
 The declarative event handlers provide a means to define rules consisting of
 declarative conditions and actions. Conditions are evaluated in the browser
 rather than the JavaScript engine which reduces roundtrip latencies and allows
 for very high efficiency.
 </p>
 
 <p>Declarative event handlers are used for example in the <a
-href="declarativeWebRequest.html">Declarative Web Request API</a> and <a
-href="declarativeContent.html">Declarative Content API</a>. This page describes
+href="declarativeWebRequest">Declarative Web Request API</a> and <a
+href="declarativeContent">Declarative Content API</a>. This page describes
 the underlying concepts of all declarative event handlers.
 </p>
 
 <h3 id="rules">Rules</h3>
 
 <p>The simplest possible rule consists of one or more conditions and one or more
 actions:</p>
 <pre>
 var rule = {
   conditions: [ /* my conditions */ ],
@@ skipping 14 matching lines @@
   id: "my rule",  // optional, will be generated if not set.
   priority: 100,  // optional, defaults to 100.
   conditions: [ /* my conditions */ ],
   actions: [ /* my actions */ ]
 };
 </pre>
 
 <h3 id="eventobjects">Event objects</h3>
 
 <p>
-<a href="events.html">Event objects</a> may support rules. These event objects
+<a href="events">Event objects</a> may support rules. These event objects
 don't call a callback function when events happen but test whether any
 registered rule has at least one fulfilled condition and execute the actions
 associated with this rule. Event objects supporting the declarative API have
 three relevant methods: $(ref:events.Event.addRules),
 $(ref:events.Event.removeRules), and
 $(ref:events.Event.getRules).
 </p>
 
 <h3 id="addingrules">Adding rules</h3>
 
@@ skipping 126 matching lines @@
 </div>
 {{/is_apps}}
 
 {{^is_apps}}
 <div class="doc-family extensions">
 <h2 id="filtered">Filtered events</h2>
 
 <p>Filtered events are a mechanism that allows listeners to specify a subset of
 events that they are interested in. A listener that makes use of a filter won't
 be invoked for events that don't pass the filter, which makes the listening
-code more declarative and efficient - an <a href="event_pages.html">event
+code more declarative and efficient - an <a href="event_pages">event
   page</a> page need not be woken up to handle events it doesn't care
 about.</p>
 
 <p>Filtered events are intended to allow a transition from manual filtering
 code like this:</p>
 
 <pre>
 chrome.webNavigation.onCommitted.addListener(function(e) {
   if (hasHostSuffix(e.url, 'google.com') ||
       hasHostSuffix(e.url, 'google.com.au')) {
@@ skipping 15 matching lines @@
 of filters that an event supports will be listed in the documentation for that
 event in the "filters" section.</p>
 
 <p>When matching URLs (as in the example above), event filters support the same
 URL matching capabilities as expressible with a
   $(ref:events.UrlFilter), except for scheme and port
 matching.</p>
 
 </div>
 {{/is_apps}}