fix sortClassName on custom fragments

[alexlamsl]

Prefer sub-optimal sort over extraneous whitespaces.

fixes #805

[silverwind]

While it doesn't really matter with this input, I prefer using non-greedy .*? so it does not match unintential parts when multiple {{}} expressions are on the same line, for example: https://regex101.com/r/M50E40/1

[alexlamsl]

I'm well aware of that, just didn't worry too much as this is a single test case of specific input.

As you can see in https://github.com/kangax/html-minifier#options-quick-reference, the default values for ignoreCustomFragments is not only non-greedy, but can also handle multi-line values in between the template markers.

Nonetheless, I'll add the ? to make it easier for your eyes. 😉

[silverwind]

LGTM, wasn't able to reproduce the issue anymore with a few variations of inputs.

var minify = require('.').minify;
var opts = {
  collapseWhitespace: true,
  ignoreCustomFragments: [/{{.*?}}/],
  sortClassName: true,
};

console.log(minify(`<span class="sprite sprite-{{sprite}}"></span>`, opts));
console.log(minify(`<span class="{{sprite}}"></span>`, opts));
console.log(minify(`<span class="{{sprite}}-sprite sprite"></span>`, opts));
console.log(minify(`<span class="sprite-{{sprite}}-sprite"></span>`, opts));
console.log(minify(`<span class={{sprite}}></span>`, opts));

[alexlamsl]

@silverwind thanks for taking a look. I've expanded the tests using your example.