Add support for `AutoIt` language

[sugatoray]

GitHub already supports AutoIt language. Please add support for AutoIt on CarbonNow.

The following code block renders color formatted AutoIt code using GitHub flavored markdown.

Local $sOutMsg = "Hello World!"
ConsoleWrite($sOutMsg & @CRLF)

What change is necessary?

Add the following to carbon/lib/constants.js here: https://github.com/carbon-app/carbon/blob/c108a251fd9edaba88638b46157421340e0b342f/lib/constants.js#L624

export const LANGUAGES = [
  // ...
  {
    name: 'AutoIt',
    mode: 'autoit',
    short: 'au3',
    highlight: true,
  },
  // ...
]