add dynamic variables to index

doc/Language/variables.pod6

@@ -1082,6 +1082,10 @@ Other compile-time variables:
 =comment There should be a better way get this table to be formatted
     properly, but if there is, Rakudo doesn't support it at the moment.
 
+X<|$*ARGFILES>X<|@*ARGS>X<|$*IN>X<|$*OUT>X<|$*ERR>X<|%*ENV>X<|$*REPO>X<|$*TZ>
+X<|$*CWD>X<|$*KERNEL>X<|$*DISTRO>X<|$*VM>X<|$*PERL>X<|$*PID>X<|$*PROGRAM-NAME>
+X<|$*PROGRAM>X<|$*EXECUTABLE>X<|$*EXECUTABLE-NAME>X<|$*USER>X<|$*GROUP>X<|$*HOME>
+X<|$*SPEC>X<|$*TMPDIR>X<|$*THREAD>X<|$*SCHEDULER>
 =table
     $*ARGFILES        | Magic command-line input handle.
     ------------------+--------------------------------------------