tdf#126397 - Make labels unique at the customization dialog

Had to add some context information for translatable captions too

Change-Id: I33117ea2455f8973742a73491b212818b9b4b9a5
Reviewed-on: https://gerrit.libreoffice.org/75622
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>
diff --git a/cui/uiconfig/ui/menuassignpage.ui b/cui/uiconfig/ui/menuassignpage.ui
index a0f0de9..f1e3308 100644
--- a/cui/uiconfig/ui/menuassignpage.ui
+++ b/cui/uiconfig/ui/menuassignpage.ui
@@ -328,7 +328,6 @@
                <property name="headers_visible">False</property>
                <property name="search_column">1</property>
                <property name="enable_tree_lines">True</property>
                <property name="show_expanders">True</property>
                <child internal-child="selection">
                  <object class="GtkTreeSelection" id="Macro Library List-selection1"/>
                </child>
@@ -363,7 +362,7 @@
            <property name="can_focus">False</property>
            <property name="halign">start</property>
            <property name="valign">start</property>
            <property name="label" translatable="yes" context="menuassignpage|contentslabel">_Function</property>
            <property name="label" translatable="yes" context="menuassignpage|contentslabel">_Available Commands</property>
            <property name="use_underline">True</property>
          </object>
          <packing>
@@ -477,7 +476,7 @@
                <property name="use_popover">False</property>
                <child internal-child="accessible">
                  <object class="AtkObject" id="menugearbtn-atkobject">
                    <property name="AtkObject::accessible-name" translatable="yes" context="menuassignpage|gearbtn">Gear Menu</property>
                    <property name="AtkObject::accessible-name" translatable="yes" context="menuassignpage|menugearbtn">Gear Menu</property>
                    <property name="AtkObject::accessible-description" translatable="yes" context="menuassignpage|menugearbtn">Contains commands to modify or delete the selected top level menu, and the command to add new top level menus.</property>
                  </object>
                </child>
@@ -499,7 +498,7 @@
                <property name="use_popover">False</property>
                <child internal-child="accessible">
                  <object class="AtkObject" id="toolbargearbtn-atkobject">
                    <property name="AtkObject::accessible-name" translatable="yes" context="menuassignpage|gearbtn">Gear Menu</property>
                    <property name="AtkObject::accessible-name" translatable="yes" context="menuassignpage|toolbargearbtn">Gear Menu</property>
                    <property name="AtkObject::accessible-description" translatable="yes" context="menuassignpage|toolbargearbtn">Contains commands to modify or delete the selected toolbar, and the command to add new toolbars.</property>
                  </object>
                </child>
@@ -886,7 +885,7 @@
            <property name="visible">True</property>
            <property name="can_focus">False</property>
            <property name="halign">start</property>
            <property name="label" translatable="yes" context="menuassignpage|functionlabel">F_unction</property>
            <property name="label" translatable="yes" context="menuassignpage|functionlabel">Assi_gned Commands</property>
            <property name="use_underline">True</property>
          </object>
          <packing>