Point documentation to openscad.org/documentation.html

src/MainWindow.ui

@@ -116,7 +116,7 @@
      <x>0</x>
      <y>0</y>
      <width>681</width>
-     <height>28</height>
+     <height>22</height>
     </rect>
    </property>
    <widget class="QMenu" name="menu_File">
@@ -625,7 +625,7 @@
   </action>
   <action name="helpActionManual">
    <property name="text">
-    <string>OpenSCAD Manual</string>
+    <string>Documentation</string>
    </property>
   </action>
   <action name="fileActionClearRecent">

src/mainwin.cc

@@ -1761,7 +1761,7 @@ MainWindow::helpHomepage()
 void
 MainWindow::helpManual()
 {
-	QDesktopServices::openUrl(QUrl("http://en.wikibooks.org/wiki/OpenSCAD_User_Manual"));
+	QDesktopServices::openUrl(QUrl("http://www.openscad.org/documentation.html"));
 }
 
 #define STRINGIFY(x) #x