Last in version-controlled changes.

This refs #2632, on with the next block.

doc/Language/control.pod6

@@ -154,7 +154,17 @@ start { sleep 1; say "done" }
 say "working";
 # working, done
 
-Note that you need a space between the C<start> and the block.
+Note that you need a space between the C<start> and the block. In the example above, the C<start> block is in sink context, since it's not assigned to a variable. From version 6.3, these kind of blocks have an exception handler attached:
+
+=for code :skip-test<Illustrates exception>
+start { die "We're dead"; }
+say "working";
+sleep 10;
+
+This code will print C<Unhandled exception in code scheduled on thread 4 We're
+dead> in version 6.d, while it will simply get out after waiting for 10 seconds
+in version 6.c. 
+
 
 The C<start {...}> immediately returns a C<Promise> that can be safely ignored
 if you are not interested in the result of the block.  If you B<are> interested