Backport 3999

[ytmimi]

Do not remove comment from an import with a single item (#3999)

[ytmimi]

I haven't had a chance to check yet, but it's likely that this backport will fix #4708 and #3984

[calebcartwright]

This has conflicts that will need to be resolved, though may be worth waiting to do so until after some other PRs land given the likely overlap of modified code

[ytmimi]

Now that we retain the comments this test case from #3984 is giving us some trouble use a::item /* comment */;

use a::item /* comment */; gets formatted as use a::item; /* comment */; Note the extra semicolon after the comment.

[ytmimi]

@calebcartwright Do you think it would be best to drop the test cases for #3984 and address that issue in a separate PR or to try and get that sorted out in this PR as well?

[ytmimi]

The backport was completed by #5853