Add updated information on putting license in META6.json

https://design.perl6.org/S22.html#license

Author: samcv

doc/Language/modules.pod6

@@ -461,6 +461,19 @@ To share your module, do the following:
     you might just use the same one that Rakudo Perl 6 uses. Just
     copy/paste the raw form of L<its license|https://github.com/rakudo/rakudo/blob/nom/LICENSE>
     into your own C<LICENSE> file.
+    
+    =item The license field in META6.json
+    The license field should be one of the standardized names listed here:
+    https://spdx.org/licenses/, in the case of the B<Artistic 2.0> license which
+    is what many of our ecosystem modules use, its identifier is
+    C<Artistic-2.0>. Having standardized identifiers make it easy for humans
+    and computers alike to know which license was actually used by looking at
+    the metadata!
+    
+    =item My license is not on spdx.org or using your own license
+    If you can't find your license on C<spdx.org> or you use your own license,
+    you should put the licenses name in the license field, and under
+    more details here https://design.perl6.org/S22.html#license
 
     =item If you don't yet have any tests, you can leave out the C<t>
     directory and C<basic.t> file for now. For more info on how to write
@@ -493,6 +506,7 @@ To share your module, do the following:
         "version" : "0.1.0",
         "description" : "Wonderful simulation to get some perspective.",
         "authors" : [ "R<Your Name>" ],
+        "license" : "Artistic-2.0",
         "provides" : {
             "Vortex::TotalPerspective" : "lib/Vortex/TotalPerspective.pm"
         },