Code quality shows `check_name`, but should show `description`

When looking at code quality summary for an issue, I realized that we're showing rather cryptic information to the user like Rubocop/Lint/UselessAssignment. It turns out the JSON output has both a check_name and a description, and it looks like we're using the former and it would be more valuable to use the latter. In this case, it's "Useless assignment to variable - user.", which is both more readable and more valuable as it names the specific variable involved.