Use new NotAMember new error format in PostTyper

[DSouzaM]

Small fix. I started implementing a new class before I realized one existed already 😃

[dottybot]

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[DSouzaM]

A test is failing because actual output:

scala> import util.foo
1 | import util.foo
  |             ^^^
  |           value `foo` is not a member of util - did you mean `util.Left`?

doesn't match expected output:

scala> import util.foo
1 | import util.foo
  |             ^^^
  |             foo is not a member of util

as a result of the change (these errors are caught by PostTyper).

Meanwhile, both actual and expected match for the following case, which is caught by TypeAssigner:

scala> import util.foo.bar
1 | import util.foo.bar
  |        ^^^^^^^^
  |        value `foo` is not a member of util - did you mean `util.Left`?

Is there a distinction between these two errors that causes them to be handled differently? Should they continue to have different error messages?

[allanrenucci]

You can update the expected output of the test case

[allanrenucci]

LGTM. Thanks!