Document .Bool on allomorphs

In Rakudo, this method is not actually implemented in allomorphs
itself and it's inherited, but in the docs it's hard to see whether
the .Bool comes from Str or Numeric portion.

Spec:       Raku/roast@4fab1d3d7c
Discussion: https://irclog.perlgeek.de/perl6-dev/2018-02-23#i_15851777

Author: zoffixznet

doc/Type/ComplexStr.pod6

@@ -36,6 +36,17 @@ directly the values can be whatever is required:
     say +$f; # OUTPUT: «42+0i␤»
     say ~$f; # OUTPUT: «"forty two (but complicated)"␤»
 
+=head2 method Bool
+
+Defined as:
+
+    multi method Bool(ComplexStr:D: --> Bool:D)
+
+I<This method may be provided by the parent classes and not implemented in ComplexStr directly>.
+
+Returns C<True> if the invocant is numerically C<±0±0i>, otherwise returns C<True>. String portion
+is not considered.
+
 =head2 method Capture
 
 Defined as:

doc/Type/IntStr.pod6

@@ -35,6 +35,17 @@ directly the values can be whatever is required:
     say +$f; # OUTPUT: «42␤»
     say ~$f; # OUTPUT: «"forty two"␤»
 
+=head2 method Bool
+
+Defined as:
+
+    multi method Bool(IntStr:D: --> Bool:D)
+
+I<This method may be provided by the parent classes and not implemented in IntStr directly>.
+
+Returns C<True> if the invocant is numerically C<0>, otherwise returns C<True>. String portion
+is not considered.
+
 =head2 method Int
 
     method Int

doc/Type/NumStr.pod6

@@ -35,6 +35,17 @@ directly the values can be whatever is required:
     say +$f; # OUTPUT: «42.1␤»
     say ~$f; # OUTPUT: «"forty two and a bit"␤»
 
+=head2 method Bool
+
+Defined as:
+
+    multi method Bool(NumStr:D: --> Bool:D)
+
+I<This method may be provided by the parent classes and not implemented in NumStr directly>.
+
+Returns C<True> if the invocant is numerically C<±0e0>, otherwise returns C<True>. String portion
+is not considered.
+
 =head2 method Num
 
     method Num

doc/Type/RatStr.pod6

@@ -35,6 +35,18 @@ directly the values can be whatever is required:
     say +$f; # OUTPUT: «42.1␤»
     say ~$f; # OUTPUT: «"forty two and a bit"␤»
 
+=head2 method Bool
+
+Defined as:
+
+    multi method Bool(RatStr:D: --> Bool:D)
+
+I<This method may be provided by the parent classes and not implemented in RatStr directly>.
+
+Returns C<True> if the numerator is the numeric portion is C<0>, otherwise returns C<True>.
+This applies for C«< 0/0 >» zero-denominator L<RatStr> as well, despite C«?< 0/0 >.Num» being
+C<True>. String portion is not considered.
+
 =head2 method Capture
 
 Defined as: