Prettier 2.4.1
[Playground link](https://prettier.io/playground/#N4Igxg9gdgLgprEAuEAdKABAZhATgdwENcATAAgHIcIA6AZzDrorPwEsYALMgCnTLIASSAFsADtAQw6SMrjgkANOgCUAbnQhFICGJhtodZKGK4I+AArEERlIQA2RAJ5HtAI1yEwAazgwAyoQicAAybFBwyFgOdHDunj5+-mJe4QDmyDC4AK5xIHAibgokCiGEUGnZhGlwAGJ4IoQw+hXIIITZMBBaIJwwIvYA6pwccHQpYHD+NhxsAG4cTm2MriDhsbgwFp5pjVExeQBWdAAe-un2cACK2RDw+-ax2im4G20MTD1iuOEwg2wkLjIAAcAAZnmZYoNPG

Android 5.0 Map is not defined

When useing TamperMonkey or GreaseMonkey with less.js as a @require resource, sometimes there will be an error.
I trace the code found a small problem.
At https://github.com/less/less.js/blob/master/packages/less/src/less-browser/utils.js
function addDataAttrs param tag may be null, then the script will exec failed.
A short if may fix this, will you please add the code to check if tag is

I'm generating json which I then include to a .styl file.

For instance;

{
    "flags": {
        "height": "198px",
        "uri": "src/images/sprites/flags.png",
        "width": "200px",
        "sprites": [
            {
                "height": "66px",
                "name": "br",
                "offsetX": "0px",
                "offsetY": "0px",
                "widt