Revert "Mention (and discourage) plan *"

This reverts commit 449bf62.

.... You can also plan "BARF" - let's not document this, especially
since it's not tested in Roast, and we'll pretend it's integer only.

Author: coke

doc/Type/Test.rakudoc

@@ -29,9 +29,6 @@ the subtest.
 If a C<plan> is used, it's not necessary to specify the end of testing with
 C<done-testing>.
 
-I<Note that C<plan *> is allowed, is the same as not declaring a plan, and is
-not recommended.>
-
 You can also provide a C<:skip-all> named argument instead of a test count,
 to indicate that you want to skip all of the tests. Such a plan will
 call L«C<exit>|/routine/exit», unless used inside of a C<subtest>.