Clarify Unicode types in ECL Lang Ref. 5.2.0-1

The question is: on p. 11 under "Unicode string constants", the text says that the constant is UTF-8 and is the same as casting to Unicode.

P. 42, however, says the UNICODE is a UTF-16 encoded. Which is it? If string constants are automatically converted to UTF-16, perhaps that should be clarified on p. 11.