Disabling/enabling cop on the current line or region

[asok]

Hi, would you accept a PR with such feature? The way I see it would work like that:

• the point is at line:

some_method rescue handle_error

• after running the new command rubocop-disable-cops the line would looke like that:

some_method rescue handle_error # rubocop:disable Style/RescueModifier

• after running the command rubocop-enable-cops the line would look like that:

some_method rescue handle_error

In case of multiple offences on a given line the commands would either disable or enable all of them. It could also work on a region - in such case it would disable given cops on multiple lines by adding the comments on the lines preceding and following the region.