Format up one or more files according to the given arguments. For
simplicity, argv is an array of strings, equivalent to the strings
that would be passed on the command line. (This isn’t a coincidence,
as we do pass in ARGV when running interactively). For a list of
options, see rdoc/rdoc.rb. By default, output will be stored in a directory
called doc below the current directory, so make sure you’re
somewhere writable before invoking.
