Change 6.d FAQ

- Clarify the expectations for new features
- Remove 6.d-prep repo; it's not for users
- Be less vague about release date

Author: zoffixznet

doc/Language/faq.pod6

@@ -34,13 +34,15 @@ implementing Perl 6.c.
 X<|v6.d (FAQ)>
 =head2 When is v6.d going to be released?
 
-Hopefully within a few months. Details at L<https://github.com/perl6/6.d-prep>
-
-You can already use some of the new features by using C<use v6.d.PREVIEW>
-L<pragma|https://docs.perl6.org/language/pragmas>. Also, many of the 6.d
-features were already implemented in 6.c compiler, due to the lack (at the
-time) of the infrastructure to support separate language versions.  Thus, when
-6.d is released, you may find you were already using many of the new features.
+There is no planned date, although L<Diwali 2018|https://en.wikipedia.org/wiki/Diwali>
+looks to be an attractive date for a release codenamed C<Diwali>.
+
+The vast majority of 6.d features are already implemented and available in
+in the Rakudo compiler, as they did not conflict with the 6.c specification.
+A smaller set of features and behaviours is available automatically if you
+use C<use v6.d.PREVIEW> pragma at the top of the file. The rest of about
+3100 new commits to the language specificication simply clarify previously
+undefined behaviour.
 
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