Comment 9 for bug 1843415

It may be my ignorance being at play here. What I mean is that kicad knows the filenames and should be able to detect conflicts of names and for case in-sensitive names. My reasoning is that we should be able to do this regard less of the user adding a new schematic or reading a project in created elsewhere. -- But we only show the warning when adding or reading it on a case in-sensitive system.