Different field labels for singular and plural

For a recent project I had several fields on a content type, that could have one or more values.

For example if you have one link you want:
Link: http://example.com/.

But if you have multiple links in the same field, you want:
Links: http://example.com/foo, http://example.com/bar.

I was surprised I didn't find a module that does this, so I experimented with it in a sandbox project.

Now I wonder if I should turn this module into a full project and create a release, or if I just didn't see an existing solution.