Minimal documentation of &*EXIT

Author: lizmat

doc/Language/variables.pod6

@@ -1131,6 +1131,10 @@ X<|$*SPEC>X<|$*TMPDIR>X<|$*THREAD>X<|$*SCHEDULER>X<|$*USAGE>
     $*PROGRAM         | Location (in the form of an C<IO::Path> object) of the
                       | Perl program being executed.
     ------------------+--------------------------------------------
+    &*EXIT            | Code that will be executed when doing an exit().  Intended
+                      | to be used in situations where Perl 6 is embedded in
+                      | another language runtime (such as Inline::Perl6 in Perl 5)
+    ------------------+--------------------------------------------
     $*EXECUTABLE      | Absolute path of the perl executable that is currently running.
     ------------------+--------------------------------------------
     $*EXECUTABLE-NAME | The name of the perl executable that is currently running.