[IMP] purchase: Rename pages titles

Purpose
=======

Change “How-To” to specific actions.

purchase/purchases/master/import.rst

@@ -1,6 +1,6 @@
-==================================
-How to import supplier pricelists?
-==================================
+==========================
+Import supplier pricelists
+==========================
 
 Introduction
 ============

purchase/purchases/master/suppliers.rst

@@ -1,6 +1,6 @@
-==========================================
-How to set several suppliers on a product?
-==========================================
+==================================
+Set several suppliers on a product
+==================================
 
 Keeping track of your vendors can be a real burden in day-to-day
 business life. Prices can change and you might have several suppliers

purchase/purchases/master/uom.rst

@@ -1,6 +1,6 @@
-=========================================================
-How to purchase in different unit of measures than sales?
-=========================================================
+=================================================
+Purchase in different unit of measures than sales
+=================================================
 
 In day-to-day business, it may happen that your supplier uses a
 different unit of measure than you do in sales. This can cause confusion

purchase/purchases/rfq.rst

@@ -1,6 +1,6 @@
-==========================================
-Request for Quotations and Purchase Orders
-==========================================
+=========================================
+Request for Quotation and Purchase Orders
+=========================================
 
 .. toctree::
    :titlesonly:

purchase/purchases/rfq/3_way_matching.rst

@@ -1,6 +1,6 @@
-=================================================================
-How to determine if a vendor bill should be paid (3-way matching)
-=================================================================
+==========================================================
+Determine if a vendor bill should be paid (3-way matching)
+==========================================================
 
 In some industries, you may receive a bill from a vendor before
 receiving the ordered products. However, the bill should maybe not be

purchase/purchases/rfq/analyze.rst

@@ -1,6 +1,6 @@
-=============================================
-How to analyze the performance of my vendors?
-=============================================
+=====================================
+Analyze the performance of my vendors
+=====================================
 
 If your company regularly buys products from several suppliers, it would
 be useful to get statistics on your purchases. There are several reasons

purchase/purchases/rfq/approvals.rst

@@ -1,6 +1,6 @@
-========================================================
-How to setup two levels of approval for purchase orders?
-========================================================
+================================================
+Setup two levels of approval for purchase orders
+================================================
 
 Two level approval setup
 ========================

purchase/purchases/rfq/bills.rst

@@ -1,6 +1,6 @@
-==============================
-How to control supplier bills?
-==============================
+======================
+Control supplier bills
+======================
 
 The **Purchase** application allows you to manage your purchase orders,
 incoming products, and vendor bills all seamlessly in one place.

purchase/purchases/rfq/cancel.rst

@@ -1,6 +1,6 @@
-================================
-How to cancel a purchase order?
-================================
+=======================
+Cancel a purchase order
+=======================
 
 Due to misunderstandings, human errors or change of plans, it is
 sometimes necessary to cancel purchase orders sent to suppliers. Odoo

purchase/purchases/rfq/create.rst

@@ -1,6 +1,6 @@
-======================================
-How to create a Request for Quotation?
-======================================
+==============================
+Create a Request for Quotation
+==============================
 
 A Request for Quotation (RfQ) is used when you plan to purchase some
 products and you would like to receive a quote for those products. In

purchase/purchases/rfq/reception.rst

@@ -1,6 +1,6 @@
-=======================================================
-How to control product received? (entirely & partially)
-=======================================================
+===============================================
+Control product received (entirely & partially)
+===============================================
 
 The **Purchase** app allows you to manage your purchase orders, to control
 products to receive and to control supplier bills.

purchase/purchases/tender/manage_multiple_offers.rst

@@ -1,6 +1,6 @@
-==============================
-How to manage Purchase Tenders
-==============================
+=======================
+Manage Purchase Tenders
+=======================
 
 A **Purchase Tender** (PT), also known as Call for Bids, is used to
 drive competition between several suppliers in order to get the best

purchase/purchases/tender/partial_purchase.rst

@@ -1,6 +1,6 @@
-=======================================================================
-How to purchase partially at two vendors for the same purchase tenders?
-=======================================================================
+===============================================================
+Purchase partially at two vendors for the same purchase tenders
+===============================================================
 
 For some Purchase Tenders (PT), you might sometimes want to be able to
 select only a part of some of the offers you received. In Odoo, this is