Documents v6.whatever

As a pragma, with some examples. Closes #2422

doc/Language/pragmas.pod6

@@ -4,10 +4,10 @@
 
 =SUBTITLE Special modules for special use
 
-In Perl 6, B<pragmas> are directive used to either identify a
-specific version of Perl 6 to be used or to modify the compiler's
-normal behavior in some way. The C<use> keyword enables a pragma (similar
-to how you can C<use> a module). To disable a pragma, use the C<no> keyword:
+In Perl 6, B<pragmas> are directive used to either identify a specific
+version of Perl 6 to be used or to modify the compiler's normal behavior
+in some way. The C<use> keyword enables a pragma (similar to how you can
+C<use> a module). To disable a pragma, use the C<no> keyword:
 
 =begin code
 use v6.c;   # use 6.c language version
@@ -19,8 +19,17 @@ pragma's purpose or a link to more details about its use.  (Note:
 Pragmas marked "[NYI]" are not yet implemented, and those marked "[TBD]"
 are to be defined later.)
 
-=comment The following should be a table but formatting in tables is
-not yet rendered properly.
+=item X<C<v6.x>|v6.x> This pragma states the version of the compiler that is going to be used,
+and turns on its features if they are optional.
+
+    use v6;   # Tells the Perl 5 interpreter this is not for it.
+    use v6.c; # Uses the "Christmas" version of Perl 6.
+    use v6.d.PREVIEW; # Turns on available "Diwali" features in v6.c
+    use v6.d; # Use "Diwali" features.
+
+Since these pragmas turn on the compiler version, they should be the
+first line in the file.
+
 
 =item X<B<MONKEY-GUTS>|MONKEY-GUTS>