Line folding breaks surrogate pairs

[Heiko Theißen]

ics/src/utils/fold-line.js

Lines 5 to 9 in 30750b1

 while (line.length > length) { 
   parts.push(line.slice(0, length)) 
   line = line.slice(length) 
   length = 74 
 } 

Consider adapting this line folding method to support surrogate pairs as described in sebbo2002/ical-generator#221.