ordered-imports: don't remove linebreaks if text contains non-whitespace characters

[lukeautry]

PR checklist

• Addresses an existing issue: fix on grouped-import is deleting export statement #4569

Overview of change:

Existing replacement code deletes lines around import declarations if they contain any line break. This means it deletes actual code in the case where a fragment of text has both line breaks and characters.

An ideal fix would be to keep the (previously deleted) code as close to the import it depends on...assuming it depends on an import at all. Of course, this ramps up the complexity, because any given line of code could use a combination of imports.

This fix results in the code just appearing below the import blocks in the order they were processed.

CHANGELOG.md entry:

[bugfix] fix linebreak handling in ordered-imports

[palantirtech]

Thanks for your interest in palantir/tslint, @lukeautry! Before we can accept your pull request, you need to sign our contributor license agreement - just visit https://cla.palantir.com/ and follow the instructions. Once you sign, I'll automatically update this pull request.

[JoshuaKGoldberg]

This LGTM until options 1 or 2 from the linked issue can be worked on. /cc @adidahiya