Document default values for native numerics

Author: zoffixznet

doc/Language/numerics.pod6

@@ -561,6 +561,13 @@ my int $a-native = -42;
 { for ^1000_000 { abs $a-native }; say now - ENTER now } # OUTPUT: «0.3088305␤»
 =end code
 
+=head2 Default Values
+
+Since there are no classes behind native types, there are no type objects you'd normally get
+with variables that haven't been initialized. Thus, native types are automatically initialized
+to zero. In 6.c language, native floating point types (C<num>, C<num32>, and C<num64>) are
+initialized to value C<NaN>; it is proposed for default to become C<0e0> in 6.d language.
+
 =head2 Native Dispatch
 
 It is possible to have native candidates alongside non-native candidates to, for example,