[IMP] (account_)payment, sale: add docstrings

Add docstrings to clarify methods in the payment link wizard.

closes odoo/odoo#100186

Signed-off-by: Antoine Vandevenne (anv) <anv@odoo.com>

addons/account_payment/wizards/payment_link_wizard.py

@@ -7,6 +7,15 @@ class PaymentLinkWizard(models.TransientModel):
     _inherit = 'payment.link.wizard'
 
     def _get_additional_link_values(self):
+        """ Override of `payment` to add `invoice_id` to the payment link values.
+
+        The other values related to the invoice are directly read from the invoice.
+
+        Note: self.ensure_one()
+
+        :return: The additional payment link values.
+        :rtype: dict
+        """
         res = super()._get_additional_link_values()
         if self.res_model != 'account.move':
             return res

addons/payment/wizards/payment_link_wizard.py

@@ -145,6 +145,13 @@ class PaymentLinkWizard(models.TransientModel):
             payment_link.link = f'{base_url}/payment/pay?{urls.url_encode(url_params)}'
 
     def _get_additional_link_values(self):
+        """ Return the additional values to append to the payment link.
+
+        Note: self.ensure_one()
+
+        :return: The additional payment link values.
+        :rtype: dict
+        """
         self.ensure_one()
         return {
             'currency_id': self.currency_id.id,

addons/sale/wizard/payment_link_wizard.py

@@ -23,6 +23,15 @@ class PaymentLinkWizard(models.TransientModel):
         return super()._get_payment_provider_available(**kwargs)
 
     def _get_additional_link_values(self):
+        """ Override of `payment` to add `sale_order_id` to the payment link values.
+
+        The other values related to the sales order are directly read from the sales order.
+
+        Note: self.ensure_one()
+
+        :return: The additional payment link values.
+        :rtype: dict
+        """
         res = super()._get_additional_link_values()
         if self.res_model != 'sale.order':
             return res