code: function checkInclude3(i) {
    const start = i;
    let l;
  
    if (l = checkAtkeyword(i)) i += l;
    else return 0;
  
    if (tokens[start + 1].value !== 'include') return 0;
  
    if (l = checkSC(i)) i += l;
    else return 0;
  
    if (l = checkIdentOrInterpolation(i)) i += l;
    else return 0;
  
    if (l = checkSC(i)) i += l;
  
    if (l = checkArguments(i)) i += l;
    else return 0;
  
    return i - start;
  }
docs: Check if token is part of an included mixin like `@include nani(foo)`
  @param {Number} i Token's index number
  @returns {Number} Length of the include