offset with muti byte character

[arzeo68]

I had an issue with multi byte character (éèêë ÉÈÊË àâ ÀÂ Çç).

I fix it by replacing the line l.266 in prettyPrinter.hpp

Before:

return data.size();

Fix:

return std::count_if(data.begin(), data.end(),[](char c) { return (static_cast<unsigned char>(c) & 0xC0) != 0x80; } );