Suppressed reference to (non-existent) $?ENC

Which does not seem to have actually existed, or been needed. Maybe in
Synopsis, together with $?TAINT; this document makes a reference to
it: https://github.com/perl6/specs/blob/master/S29-functions.pod

However, it's not implemented (nor anything like that), so this
closes #2724 and moves around the surrounding to say the same,
although this needs to be restructured too.

Author: JJ

doc/Language/5to6-perlvar.pod6

@@ -583,16 +583,11 @@ therefore, as stated before, the C<$!> variable holds the exception object.
 
 =item $^D
 
-Currently no equivalents for either of these variables.
-
 =item ${^ENCODING}
 
-Although deprecated in Perl 5, this may have some sort of equivalent in
-C<$?ENC>, but this is far from clear.
-
 =item ${^GLOBAL_PHASE}
 
-No Perl 6 equivalent.
+Currently no equivalents for either of these variables.
 
 =item $^H
 
@@ -633,4 +628,4 @@ already, there should be no need to tell you how to use them in Perl 6.
 
 =end pod
 
-# vim: expandtab softtabstop=4 shiftwidth=4 ft=perl6
+# vim: expandtab softtabstop=4 shiftwidth=4 ft=perl6