[FIX] purchase: include refunds in invoice count

If a supplier had a refund, it was not included in the supplier invoice count
nor in the results in the statbutton

On the customer side, fields like total_invoiced works on both the out_invoice
and out_refund

addons/purchase/models/res_partner.py

@@ -19,7 +19,7 @@ class res_partner(models.Model):
     def _compute_supplier_invoice_count(self):
         Invoice = self.env['account.invoice']
         for partner in self:
-            partner.supplier_invoice_count = Invoice.search_count([('partner_id', 'child_of', partner.id), ('type', '=', 'in_invoice')])
+            partner.supplier_invoice_count = Invoice.search_count([('partner_id', 'child_of', partner.id), ('type', 'in', ('in_invoice', 'in_refund'))])
 
     @api.model
     def _commercial_fields(self):

addons/purchase/views/res_partner_views.xml

@@ -52,7 +52,7 @@
             <field name="res_model">account.invoice</field>
             <field name="view_type">form</field>
             <field name="view_mode">tree,form,graph</field>
-            <field name="domain">[('type','=','in_invoice')]</field>
+            <field name="domain">[('type','in',('in_invoice', 'in_refund'))]</field>
             <field name="context">{'search_default_partner_id': active_id, 'default_type': 'in_invoice', 'type': 'in_invoice', 'journal_type': 'purchase'}</field>
             <field name="help" type="html">
                 <p class="o_view_nocontent_smiling_face">