Merge branch 'potatosalad/fix-restricted-shell-user-defined-functions' into maint

* potatosalad/fix-restricted-shell-user-defined-functions:
  Fix user-defined function support when using the restricted shell.

OTP-19833

Author: frazze-jobb

lib/stdlib/src/shell.erl

@@ -1159,7 +1159,7 @@ not_restricted(exit, []) ->
     true;
 not_restricted(fl, []) ->
     true;
-not_restricted(fd, [_,_]) ->
+not_restricted(fd, [_,_,_]) ->
     true;
 not_restricted(ft, [_]) ->
     true;