Incorrect span with bad imports

[emberian]

use foo::bar;

generates:

k.rs:1:4: 1:13 error: unresolved name
k.rs:1 use foo::bar;
           ^~~~~~~~~
k.rs:1:4: 1:13 error: failed to resolve import: foo::bar
k.rs:1 use foo::bar;
           ^~~~~~~~~
error: failed to resolve imports
error: aborting due to 3 previous errors

I believe the span on the first error should just cover foo, not the whole path (that is a path, yes?)

[bstrie]

This would clean up the final detail of #3027.

[jdm]

Was this closed because it can no longer be reproduced?

[emberian]

I fixed it in #6347, partially, and have a few more patches to fix up the other cases.