#3433 moved the definition of options to our internal parsers but there's still a bit of work to support external plugins defining new options:

Use cases:

• This should include the options contributed by plugins:

  prettier --plugin @prettier/plugin-python --help

• CLI should work:

  prettier --plugin my-cool-prettier-plugin --my-custom-option

• Remove unknown option warning for options contributed by external plugins.

  prettier.format('def foo(): pass', {
    parser: 'python',
    plugins: ['@prettier/plugin-python'],
    pythonVersion: '3.1.4'
  })
  ● Validation Warning:
  
   Unknown option "pythonVersion" with value "3.1.4" was found.
   This is probably a typing mistake. Fixing it will remove this message.