Attempt to document Baggy.invert

gistfile1.txt

=head2 method invert

Defined as:

    method invert(Baggy:D:) returns Seq:D

Returns all elements and their respective weights as a L<Seq|/type/Seq> of L<Pairs|/type/Pair>,
where the element itself is the value and the weight of that element is the key, i.e.
the opposite of method L<pairs|#method pairs>. Except for some esoteric cases C<invert> on a
Baggy type returns the same result as L<antipairs|#method_antipairs>.

    my $breakfast = bag <bacon eggs bacon>;
    my $seq = $breakfast.invert;
    say $seq.sort;                                    # (1 => eggs 2 => bacon)