Add babili flag to documentation and fix typo

[pdehaan]

$ node cli --version # 0.8.0

$ node cli --help
cli

Options:
  --why, -w      Show package content                                  [boolean]
  --babili       Use babili minifier                                   [boolean]
  --version, -v  Show version number                                   [boolean]
  --help, -h     Show help                                             [boolean]

Size Limit will read size-limit section from package.json.
Configuration example:

  "size-limit": [
    {
      "path": "index.js",
      "limit": "9 KB",
      "babili": true
    }
  ]

[ai]

Released in 0.8.1