Autodetects the encoding of the XML document supplied by the given
input stream.
Encoding autodetection is done according to the XML 1.0 specification,
Appendix F.1: Detection Without External Encoding Information.
Parameters: err - The error dispatcher Two-element array, where the first element (of typejava.lang.String) contains the name of the autodetected encoding, andthe second element (of type java.lang.Boolean) specifies whether the encoding was specified by the encoding attribute of an XML declaration(prolog).