Remove "Help" button from new diff UI

This has never been hooked up to anything.

Author: kaiw

meld/resources/ui/new-diff-tab.ui

@@ -442,21 +442,6 @@
             <property name="visible">True</property>
             <property name="can-focus">False</property>
             <property name="spacing">6</property>
-            <child>
-              <object class="GtkButton" id="button_help">
-                <property name="label">gtk-help</property>
-                <property name="use_action_appearance">False</property>
-                <property name="can_focus">True</property>
-                <property name="receives_default">True</property>
-                <property name="use_stock">True</property>
-              </object>
-              <packing>
-                <property name="expand">False</property>
-                <property name="fill">False</property>
-                <property name="position">0</property>
-                <property name="secondary">True</property>
-              </packing>
-            </child>
             <property name="layout-style">end</property>
             <child>
               <object class="GtkButton" id="button_new_blank">
@@ -472,7 +457,7 @@
               <packing>
                 <property name="expand">False</property>
                 <property name="fill">False</property>
-                <property name="position">1</property>
+                <property name="position">0</property>
               </packing>
             </child>
             <child>
@@ -489,7 +474,7 @@
               <packing>
                 <property name="expand">False</property>
                 <property name="fill">False</property>
-                <property name="position">2</property>
+                <property name="position">1</property>
               </packing>
             </child>
           </object>