It has been pointed out by Moritz Schubotz in an EOSC task force discussion that it is useful to be able to point to fragments of code in a diff, not just in a file.
Here is an example of what can be done in GitHub today:
It would be nice to provide a similar functionality in Software Heritage.
Thank you for reporting @rdicosmo .
Just for clarification:
The example might not been chosen optimal. The lines I selected above are just automated white-space adjustments performed by the IDE not really relevant for the pull request. What was actually done in the pull request is more apparent in the test case
where white spaces in the LaTeX code were removed.