parsingErrorAppendage constant

Implementation

static const String parsingErrorAppendage = "Only ES5 is supported. "
    "Key words such as let, const, operators such as -> and templated strings are not yet supported. "
    "Here's a full list of features that are only available in ES6 and are therefore NOT supported in Ensemble at this time. https://www.w3schools.com/js/js_es6.asp";