fixed "no-unused-variable" argument count

[knafteN]

PR checklist

• Addresses an existing issue: fixes Wrong JSDoc for "no-unused-variable" rule #4659
• New feature, bugfix, or enhancement
  • Includes tests
• Documentation update

Overview of change:

fixed "no-unused-variable" argument count, see linked issue

[palantirtech]

Thanks for your interest in palantir/tslint, @knafteN! 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]

Looks good, thanks for sending this in @knafteN! Once you sign the CLA we can merge it in.

[knafteN]

@JoshuaKGoldberg done :]