[IMP]purchase_*: Improvement in model description

Purpose of this commit is to give description more "business oriented"
because those descriptions appears in Odoo Studio which is supposed to be used by end users, not only by developers.

Related Task ID : 37311

addons/purchase/report/purchase_bill.py

@@ -7,7 +7,7 @@ from odoo.tools import formatLang
 class PurchaseBillUnion(models.Model):
     _name = 'purchase.bill.union'
     _auto = False
-    _description = 'Bills & Purchases'
+    _description = 'Purchases & Bills Union'
     _order = "purchase_order_id desc, vendor_bill_id desc"
 
     name = fields.Char(string='Reference', readonly=True)

addons/purchase/report/purchase_report.py

@@ -10,7 +10,7 @@ from odoo import api, fields, models, tools
 
 class PurchaseReport(models.Model):
     _name = "purchase.report"
-    _description = "Purchases Orders"
+    _description = "Purchase Report"
     _auto = False
     _order = 'date_order desc, price_total desc'
 

addons/purchase_requisition/models/purchase_requisition.py

@@ -19,7 +19,7 @@ PURCHASE_REQUISITION_STATES = [
 
 class PurchaseRequisitionType(models.Model):
     _name = "purchase.requisition.type"
-    _description = "Purchase Agreement Type"
+    _description = "Purchase Requisition Type"
     _order = "sequence"
 
     name = fields.Char(string='Agreement Type', required=True, translate=True)