One very simple solution is to extend the multiline string syntax to allow any number (at least 3) of double-quote characters as the delimiter:
let myVeryExcellentString = """"""""""""
let address = """
John Jacob Jingleheimer Schmidt
555 Main Street
Lake Wobegon, MN
"""
print("\(address)")
""""""""""""
If at least 4 double-quotes are used, then it is a raw string where nothing is escaped.