Display target quantity of order point on list view

The target quantity is always required and visible.

modules/stock_supply/view/order_point_tree.xml

@@ -7,5 +7,6 @@ this repository contains the full copyright notices and license terms. -->
     <field name="location" expand="2"/>
     <field name="type"/>
     <field name="min_quantity" symbol="unit"/>
+    <field name="target_quantity" symbol="unit"/>
     <field name="max_quantity" symbol="unit"/>
 </tree>