this change includes the following changes:
- a macro option must be #1–#9
- add \providecommand
- add starred versions of \newcommand, \newenvironment, and their
variants
- add number of arguments to \(re)newenvironment
a35040f795
Co-authored-by: Eisuke Kawashima <e-kwsm@users.noreply.github.com>