docs Clarified some things to improve understanding

doc/user/project/integrations/custom_issue_tracker.md

@@ -3,7 +3,7 @@
 To enable the Custom Issue Tracker integration in a project, navigate to the
 [Integrations page](project_services.md#accessing-the-project-services), click
 the **Customer Issue Tracker** service, and fill in the required details on the page as described
-in the table below.
+in the table below. You will be able to edit the title and description later as well.
 
 | Field | Description |
 | ----- | ----------- |
@@ -17,6 +17,9 @@ Once you have configured and enabled Custom Issue Tracker Service you'll see a l
 
 ## Referencing issues
 
-- Issues are referenced with `ANYTHING-<ID>`, where `ANYTHING` can be any string and `<ID>` is a number used in the target project of the custom integration (example `PROJECT-143`).
+- Issues are referenced with `ANYTHING-<ID>`, where `ANYTHING` can be any string in CAPS and `<ID>`
+is a number used in the target project of the custom integration (for example, `PROJECT-143`).
 - `ANYTHING` is a placeholder to differentiate against GitLab issues, which are referenced with `#<ID>`. You can use a project name or project key to replace it for example.
-- So with the example above, `PROJECT-143` would refer to `https://customissuetracker.com/project-name/143`.
+- When building the hyperlink, the `ANYTHING` part is ignored, and links always point to the address
+specified in `issues_url`, so in the example above, `PROJECT-143` would refer to
+`https://customissuetracker.com/project-name/143`.