Change file extension of "Ant" Guide documents to 'html'

The HTML validator only checks .html files, but not .htm files.

Author: ptziegler

eclipse.platform.common/bundles/org.eclipse.platform.doc.isv/guide/ant_contributing_task.htm renamed to eclipse.platform.common/bundles/org.eclipse.platform.doc.isv/guide/ant_contributing_task.html

@@ -52,6 +52,6 @@ <h2>
  explictly generates the tasks JAR when triggered on specific resource changes.
 </p>  
 
-<p>Also see <a href="ant_contributing_task.htm">Contributing tasks and types</a>.</p>
+<p>Also see <a href="ant_contributing_task.html">Contributing tasks and types</a>.</p>
 
 </BODY></HTML>

eclipse.platform.common/bundles/org.eclipse.platform.doc.isv/guide/ant_developing.htm renamed to eclipse.platform.common/bundles/org.eclipse.platform.doc.isv/guide/ant_developing.html

@@ -37,7 +37,7 @@ <h2>
 }</pre>
 
 <p>If a progress monitor is used, it is made available for the running tasks.
-See <a href="./ant_contributing_task.htm#monitor">Progress Monitors</a> for more details.
+See <a href="./ant_contributing_task.html#monitor">Progress Monitors</a> for more details.
 </p><p>Note that only one Ant build can occur at any given time if the builds do not occur in separate VMs. See <a href="../reference/api/org/eclipse/ant/core/AntRunner.html#isBuildRunning()">
 AntRunner.isBuildRunning()</a>;
 </p>

eclipse.platform.common/bundles/org.eclipse.platform.doc.isv/guide/ant_eclipse_tasks.htm renamed to eclipse.platform.common/bundles/org.eclipse.platform.doc.isv/guide/ant_eclipse_tasks.html

@@ -317,12 +317,12 @@
 		</topic>
 	</topic>
 
-	<topic label="Platform Ant support" href="guide/ant.htm">
-		<topic label="Running Ant buildfiles programmatically" href="guide/ant_running_buildfiles_programmatically.htm" />
-		<topic label="Ant tasks provided by the platform" href="guide/ant_eclipse_tasks.htm" />
-		<topic label="Contributing tasks and types" href="guide/ant_contributing_task.htm" />
-		<topic label="Developing Ant tasks and types within Eclipse" href="guide/ant_developing.htm" />
-		<topic label="Expanding the Ant classpath" href="guide/ant_expanding_classpath.htm" />
+	<topic label="Platform Ant support" href="guide/ant.html">
+		<topic label="Running Ant buildfiles programmatically" href="guide/ant_running_buildfiles_programmatically.html" />
+		<topic label="Ant tasks provided by the platform" href="guide/ant_eclipse_tasks.html" />
+		<topic label="Contributing tasks and types" href="guide/ant_contributing_task.html" />
+		<topic label="Developing Ant tasks and types within Eclipse" href="guide/ant_developing.html" />
+		<topic label="Expanding the Ant classpath" href="guide/ant_expanding_classpath.html" />
 	</topic>
 
 	<topic label="User assistance support" href="guide/ua.htm">