[DMN Designer] DMN Editor missing xml-prolog for UTF-8 encoding

I assume the DMN Editor always saves content as UTF-8.
In this case, when the Editor runs on Win10 which might have different OS Platform defaults, it is even more required to insert correct xml-prolog, such as

<?xml version="1.0" encoding="UTF-8"?>

without xml-prolog and without UTF8 bom, one can only rely on heuristics which not being deterministic may fail on different platform.