Is your feature request related to a problem? Please describe.

Apologies if this is a duplicate or if it is not the correct repository.

I've encountered a hardcoded '/dev/null' and am wondering if it would be useful to have a cop to detect this misuse.

I've also searched for occurrences on GitHub, and it appears to be quite common:

https://github.com/search?q=%22%27%2Fdev%2Fnull%27%22+language%3ARuby+path%3A.rb&type=code

Describe the solution you'd like

A cop that can detect '/dev/null' or "/dev/null" and suggest using File::NULL instead.

File::NULL has been introduced in Ruby 1.9.3

Describe alternatives you've considered

n/a

Additional context

The cop should detect for exactly '/dev/null' or "/dev/null", because most Rakefiles contain /dev/null as part of a command (like >> /dev/null) (and I guess they are platform-dependent

A CI failing on windows because of '/dev/null'

jamesmartin/inline_svg#174