fixes spelling mistake #2632

I had misunderstood it and instead of writing version 6.d I wrote 6.2.

doc/Type/Seq.pod6

@@ -45,7 +45,7 @@ B<Caution:> No program should ever assume a C<Seq> may only be iterated once
 even if not cached by the program. Caching is a volatile state exposed to the
 developer as an optimization. The C<Seq> may become cached by many operations,
 including calling C<perl> on the C<Seq> (if called prior to a non-cached
-iteration). From version 6.2, you C<.perl> can be called on consumed <Seq>. If a program assumes a Seq can only iterate once, but then is
+iteration). From version 6.d, you C<.perl> can be called on consumed <Seq>. If a program assumes a Seq can only iterate once, but then is
 later changed to call one of these operations during the loop, that assumption
 will fail.