[IMP] digest: update documentation links

Purpose
=======
Update documentation links for digest in settings menu.

Task-2800588

closes odoo/odoo#87351

X-original-commit: ca7502b0c2d46dd16547272cec0265c8c4aeca8e
Signed-off-by: Thibault Delavallee (tde) <tde@openerp.com>

addons/digest/views/digest_views.xml

@@ -56,8 +56,7 @@
                                 <group name="kpi_sales"/>
                                 <group name="custom" string="Custom" groups="base.group_system">
                                     <p>Want to add your own KPIs?<br />
-                                    <!-- TODO: change to actual documentation link!!! -->
-                                    <a href="https://www.odoo.com/documentation/" target="_blank"><i class="fa fa-arrow-right"></i> Check our Documentation</a></p>
+                                    <a href="https://www.odoo.com/documentation/saas-15.1/applications/general/digest_emails.html#custom-digest-emails" target="_blank"><i class="fa fa-arrow-right"></i> Check our Documentation</a></p>
                                 </group>
                             </group>
                         </page>

addons/digest/views/res_config_settings_views.xml

@@ -17,6 +17,7 @@
                             </div>
                             <div class="o_setting_right_pane">
                                 <label string="Digest Email" for="digest_emails"/>
+                                <a href="https://www.odoo.com/documentation/saas-15.1/applications/general/digest_emails.html" title="Documentation" class="ml-1 o_doc_link" target="_blank"></a>
                                 <div class="text-muted" id="msg_module_digest">
                                     Add new users as recipient of a periodic email with key metrics
                                 </div>