Remove erroneous X-ref for &?BLOCK

Author: lizmat

doc/Language/variables.pod6

@@ -1143,7 +1143,7 @@ C<$!> is set to the C<Any> type object.
 Note that C<CATCH> blocks I<do not> set C<$!>. Rather, they set C<$_> inside
 the block to the caught exception.
 
-X<|$?FILE>X<|$?LINE>X<|::?CLASS>X<|&?BLOCK>X<|%?RESOURCES>
+X<|$?FILE>X<|$?LINE>X<|::?CLASS>X<|%?RESOURCES>
 =head2 Compile-time variables
 
 All compile time variables have a question mark as part of the twigil. Being