Create META.info files not META6.json files

Assuming that's what everyone wants now, since that's all that seems to be used.

doc/Language/modules.pod6

@@ -415,7 +415,7 @@ To share your module, do the following:
         |   `-- Vortex
         |       `-- TotalPerspective.pod6
         |-- LICENSE
-        |-- META6.json
+        |-- META.info
         |-- README.md
         `-- t
             `-- basic.t
@@ -465,7 +465,7 @@ To share your module, do the following:
     »
 
     =begin item
-    Make your C<META6.json> file look something like this:
+    Make your C<META.info> file look something like this:
 
     =for code :allow<R>
     {
@@ -506,7 +506,7 @@ To share your module, do the following:
     C<%?RESOURCES> Hash indexed on the name provided.
 
     The L<Test::META module | https://github.com/jonathanstowe/Test-META/>
-    can help you check the correctness of the META6.json file.  See the full
+    can help you check the correctness of the META.info file.  See the full
     L<META specification | https://design.perl6.org/S22.html#META6.json> for
     more details as well as further options available for use in
     C<META6.json> files.