Add E0790 as more specific variant of E0283

[aticu]

Fixes #81701

I think this should be good to go, there are only two things where I am somewhat unsure:

• Is there a better way to get the fully-qualified path for the suggestion? I tried self.tcx.def_path_str, but that didn't seem to always give a correct path for the context.
• Should all this be extracted into it's own method or is it fine where it is?

r? @estebank