slight reword; add explicit example; add macros

Author: coke

doc/Language/experimental.pod6

@@ -4,13 +4,14 @@
 
 =SUBTITLE New features for brave users
 
-During Perl 6 development, new features are often made available on
-the main branch.  Eventually they may be incorporated into the next
-version of Perl 6.  To use such features, one uses the C<experimental>
-pragma in program source code like this:
+During Perl 6 development, new features are often made available for
+users to experimental with before their design is completed. Eventually
+these features may be made part of the Perl 6 specification.  To use these
+features, one uses the C<experimental> pragma in program source code, for
+example, like this:
 
 =begin code
-use experimental;
+use experimental :macros;
 =end code
 
 Following is a list of current experimental features and a short
@@ -23,6 +24,8 @@ not yet rendered properly.
 
 =item X<B<cache>|cache> [TBD]
 
+=item X<B<macros>|macros> [TBD]
+
 =item X<B<pack>|pack> [TBD]
 
 =end pod