Documentation for `--jobs` suggests you could omit a value, but it's required

[dgholz]

Trying to run my Ruby builds as swiftly as possible with ruby-install -j 3.2.2 gives:

Stable ruby versions:
  ruby:
    2.7.8
    3.0.6
    3.1.4
    3.2.2
  jruby:
    9.4.3.0
  truffleruby:
    23.0.0
  truffleruby-graalvm:
    23.0.0
  mruby:
    3.0.0

The man page says:

       -j[JOBS], --jobs[=JOBS]
              Specifies the number of make jobs to run in parallel when compiling Ruby. If the -j option is provided without an
              argument, make will allow an unlimited number of simultaneous jobs.

But the code always treats the argument following --jobs/-j as the number of make jobs. The command-line help is pretty similar:

    -j[JOBS], --jobs[=JOBS] Number of jobs to run in parallel when compiling

Where [VALUE] usually mean 'optional', by convention.

[dgholz]

Thanks!