[IMP] mrp: add sequence of work order in the display name

In order to clarify the flow of work order in calendar and gantt view,
add the sequence number of WO by MO. This sequence is
compute during the call of the "name_get".

task-2082261

addons/mrp/models/mrp_workorder.py

@@ -236,7 +236,7 @@ class MrpWorkorder(models.Model):
         (self - treated).allowed_lots_domain = False
 
     def name_get(self):
-        return [(wo.id, "%s - %s - %s" % (wo.production_id.name, wo.product_id.name, wo.name)) for wo in self]
+        return [(wo.id, "%s. %s - %s - %s" % (wo.production_id.workorder_ids.ids.index(wo.id) + 1, wo.production_id.name, wo.product_id.name, wo.name)) for wo in self]
 
     def unlink(self):
         # Removes references to workorder to avoid Validation Error