Correct with source location info rather than regexp in UnusedArgument
Organize UnusedMethodArgument spec
Avoid suggesting underscore-prefixed name for unused keyword arguments

Related to #1177.
Avoid auto-correcting unused keyword arguments

This fixes #1177.
Merge pull request #1180 from yujinakayama/fix-invalid-correction-for-unused-keyword-arg

Fix invalid auto-correction for unused keyword arguments