[ruby/logger] Mention File::Null in Logger#new document
File::Null
https://github.com/ruby/logger/commit/2e772770be
Added by pocke (Masataka Kuwabara) about 5 years ago
[ruby/logger] Mention
File::Nullin Logger#new documenthttps://github.com/ruby/logger/commit/2e772770be