function sinh( x ) {
	return addon( x );
}
Computes the hyperbolic sine of a double-precision floating-point number.

@private
@param {number} x - input value
@returns {number} hyperbolic sine

@example
var v = sinh( 0.0 );
// returns 0.0

@example
var v = sinh( 2.0 );
// returns ~3.627

@example
var v = sinh( -2.0 );
// returns ~-3.627

@example
var v = sinh( NaN );
// returns NaN