Document Rational.new normalizes ZDRs

Author: zoffixznet

doc/Type/Rational.pod6

@@ -24,7 +24,10 @@ Please note that, since C<DeT> is by default equal to C<NuT>, in this case both
 =for code :skip-test
 method new(NuT:D: $numerator, DeT:D: $denominator --> Rational:D)
 
-Creates a new rational object from numerator and denominator.
+Creates a new rational object from numerator and denominator, which it
+normalizes to the lowest terms. The C<$denominator> can be zero, in which
+case the numerator is normalized to C<-1>, C<0>, or C<1> depending on whether
+the original is negative, zero, or positive, respectively.
 
 =head2 method Bool