Show the urlTemplate of External IDs in the edit form

Currently, it is unclear to contributors, that there are urlTemplates for External IDs. As an example, we defined for the external ID service GitHub the url template https://github.com/{source-item-id}. We expect that contributors respect this url template and therefore do not add the https://github.com/-part to their entry. But currently, the frontend does not give any indications, that such url template exists and there are also no instructions, how to interpret it. Is there a quick solution possible for this issue? I don't mind how it is solved in the UI, maybe it is enough that there is a information label: Please enter the identifier based on the url template: {urlTemplate}

@lbarbot Do you have a proposal how to solve it in the edit form?