Fix copying text from a diff.
Review Request #13244 — Created Aug. 28, 2023 and submitted
At some point in the past (years ago), the code managing smart copying
of diff content to the clipboard had broken due to a function being
renamed and being made part of a prototype.
This change fixes that by updating the calls, pointing to the corrected
This will be backported to 5.x.
Successfully copied code without issues.