Ruby

[ruby/irb] Add edit command (https://github.com/ruby/irb/pull/453)

• Add edit command

• Make find_source a public singleton method

• Add document for the edit command

• Make find_end private

• Remove duplicated private

https://github.com/ruby/irb/commit/4321674aa7
Co-authored-by: Takashi Kokubun [email protected]