[Issue 22920] New: Improve errors when missing import paths

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=22920

          Issue ID: 22920
           Summary: Improve errors when missing import paths
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: dmd
          Assignee: nobody at puremagic.com
          Reporter: contact at lsferreira.net

When an import path is missing, we are not using errorSupplemental, so the
error alignment is weird:

---

fail_compilation/test22361.d(11): Error: unable to read module
`this_module_does_not_exist`
fail_compilation/test22361.d(11):        Expected
'this_module_does_not_exist.d' or 'this_module_does_not_exist/package.d' in one
of the following import paths:
import path[0] = fail_compilation
import path[1] = $p:druntime/import$
import path[2] = $p:phobos$

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