Make `Zero` and `One` extensional traits#122

qryxip wants to merge 4 commits intorust-lang-ja:masterrust-lang-ja/ac-library-rs:masterfrom

qryxip:make-zero-and-one-extensional-traitqryxip/ac-library-rs:make-zero-and-one-extensional-traitCopy head branch name to clipboard