Gets the terminator character(s) of this line.
This predicate may return:
- the empty string if this line is the last line in a file and there is no line terminator after it;
- a single-character string containing the character
\u2028(Unicode character LINE SEPARATOR) or
\u2029(Unicode character PARAGRAPH SEPARATOR);
- the two-character string
\r\n(carriage return followed by newline).