Regenerate .rubocop_todo.yml
Remove useless assignment
Use safe assignment in condition
Avoid prefixing reader method name with `get_`
Remove `self.Filter` and `self.Suggest`

Replace them with `Filter.new` and `Suggest.new` respectively.
Use `attr_reader` to define trivial reader methods
Use `_` prefix in unused argument name
Avoid using prefix `_` for a used variable
Keep line length to 80
Merge pull request #23 from yous/patch-rubocop

Reduce RuboCop offenses