Add help button to signature line dialogs

Change-Id: I984889c374333a7c76dac0221334366cfdf471ee
Reviewed-on: https://gerrit.libreoffice.org/53106Reviewed-by: Samuel Mehrbrodt <Samuel.Mehrbrodt@cib.de>
Tested-by: Samuel Mehrbrodt <Samuel.Mehrbrodt@cib.de>

cui/uiconfig/ui/signatureline.ui

@@ -49,6 +49,21 @@
                 <property name="position">1</property>
               </packing>
             </child>
+            <child>
+              <object class="GtkButton" id="help">
+                <property name="label">gtk-help</property>
+                <property name="visible">True</property>
+                <property name="can_focus">True</property>
+                <property name="receives_default">True</property>
+                <property name="use_stock">True</property>
+              </object>
+              <packing>
+                <property name="expand">True</property>
+                <property name="fill">True</property>
+                <property name="position">2</property>
+                <property name="secondary">True</property>
+              </packing>
+            </child>
           </object>
           <packing>
             <property name="expand">False</property>
@@ -307,8 +322,5 @@
       <action-widget response="-6">cancel</action-widget>
       <action-widget response="-5">ok</action-widget>
     </action-widgets>
-    <child>
-      <placeholder/>
-    </child>
   </object>
 </interface>

cui/uiconfig/ui/signsignatureline.ui

@@ -48,6 +48,20 @@
                 <property name="position">1</property>
               </packing>
             </child>
+            <child>
+              <object class="GtkButton" id="help">
+                <property name="label">gtk-help</property>
+                <property name="visible">True</property>
+                <property name="can_focus">True</property>
+                <property name="receives_default">True</property>
+                <property name="use_stock">True</property>
+              </object>
+              <packing>
+                <property name="expand">True</property>
+                <property name="fill">True</property>
+                <property name="position">2</property>
+              </packing>
+            </child>
           </object>
           <packing>
             <property name="expand">False</property>