Changes again indexing of ??!! operator

It's now indexed as `infix`. This would be the 4th time we close #1851. Will this be the last one?
Who knows...

doc/Language/operators.pod6

@@ -1922,9 +1922,9 @@ my %loser = points => 20, misses => 10;
 
 =head1 Conditional Operator Precedence
 
-=head2 infix C<?? !!> X<|operator,conditional>
+=head2 infix C<?? !!>
 
-Also called X<Ternary operator|?? !!> or conditional operator.
+Also called X<ternary operator|operator,ternary> or X<conditional operator|operator,conditional>.
 
 C<$condition ?? $true !! $false> evaluates C<$condition> and returns the expression right behind ??, in this case C<$true> if it is C<True>, otherwise evaluates and returns the expression behind !!, C<$false> in this case.