Add newline if prefix ends in comment without one

What does this merge request do and why?

When processing code generation suggestions, check to see if the prefix ends in a comment and without a newline, then check to see if adding a newline would produce valid code. If so add a newline to prevent the suggestion from being inserted into a comment

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

Merge request checklist

• Tests added for new functionality. If not, please raise an issue to follow up.
• Documentation added/updated, if needed.