[IMP] purchase: added more meaningful error message

While confirming the quotation if there is no seller
who's matching the requirements at that time error
message was not clean.
So that, changed that message to a more meaningful
new message.

TaskID - 1948751

closes odoo/odoo#32644

Signed-off-by: Arnold Moyaux <amoyaux@users.noreply.github.com>

addons/purchase_stock/models/stock_rule.py

@@ -45,7 +45,7 @@ class StockRule(models.Model):
                 uom_id=procurement.product_uom)
 
             if not supplier:
-                msg = _('There is no vendor associated to the product %s. Please define a vendor for this product.') % (procurement.product_id.display_name,)
+                msg = _('There is no matching vendor price to generate the purchase order for product %s (no vendor defined, minimum quantity not reached, dates not valid, ...). Go on the product form and complete the list of vendors.') % (procurement.product_id.display_name)
                 raise UserError(msg)
 
             partner = supplier.name