"?" alias ignored

[stevenvachon]

const options = require('optionator')({
  options: [{
    option: 'help',
    alias: '?',
    type: 'Boolean'
  }]
}).parse('-?');

console.log(options);
//-> { _: [ '-?' ] }

[gkz]

When we parse options, we assume the option name passes the regex:

[a-zA-Z][-a-zA-Z0-9]*

We can maybe expand this to cover more cases.

[stevenvachon]

I've seen a number of Windows/DOS commands that use -? for accessing the help screen, so it'd be a nice enhancement.