subtest can use either order.

modified version of PR#4513 from @JJ

Author: coke

doc/Type/Test.rakudoc

@@ -648,7 +648,7 @@ subtest {
 =end code
 
 You can also place the description as the first positional argument, or use a
-L<C<Pair>|/type/Pair> with description as the key and subtest's code as the value. This can be
+L<C<Pair>|/type/Pair> with the description and the code in either order. This can be
 useful for subtests with large bodies.
 
 =begin code :preamble<use Test;>
@@ -658,11 +658,13 @@ subtest 'A bunch of tests', {
     ...
 }
 
-subtest 'Another bunch of tests' => {
+subtest {
     plan 72;
     ...
     ...
-}
+} => 'Another bunch of tests';
+
+
 =end code
 
 =head2 sub todo