Determines whether a UTF-16 character is defined as a surrogate in the Unicode specifications.

class function IsSurrogate(Surrogate: Char): Boolean; overload;
class function IsSurrogate(const S: string; Index: Integer): Boolean; overload; static;

__fastcall Boolean IsSurrogate(Char Surrogate);
static __fastcall Boolean IsSurrogate(const AnsiString S, int Index);