Mention the replacement for magic __SUB__ constant

Anthony Parsons · Anthony Parsons · commit 099643400f90 · 2013-01-15T21:22:57.000Z
(It was added in 5.16.0)
diff --git a/S02-bits.pod b/S02-bits.pod
@@ -4263,6 +4263,7 @@ The double-underscore forms are going away:
     __LINE__            $?LINE
     __FILE__            $?FILE
     __PACKAGE__         $?PACKAGE
+    __SUB__             $?ROUTINE
     __END__             =begin END
     __DATA__            =begin DATA
 
