[FIX] mrp_subcontracting: rename record component button

There is a button in the header to register subcontracting process
(when needed). And there is an additional button in the view with
the purpose to correct data later after the encoding. However we
can't set button with optional="hide". We rename it with an edit
icon

Part-of: odoo/odoo#140307

addons/mrp_subcontracting/views/stock_picking_views.xml

@@ -12,10 +12,9 @@
             </xpath>
             <xpath expr="//field[@name='move_ids_without_package']//tree" position="inside">
                 <field name="show_subcontracting_details_visible" column_invisible="True"/>
-                <button name="action_show_subcontract_details" string="Register components for subcontracted product" type="object" icon="fa-sitemap"
+                <button name="action_show_subcontract_details" string="Subcontracting" type="object" icon="fa-pencil"
                     invisible="not show_subcontracting_details_visible"/>
             </xpath>
         </field>
     </record>
 </odoo>
-