[6.d] Update output examples for sunk start

To match updated PoV and propspec:
rakudo/rakudo@15c16e35ade24c6f0077
Raku/roast@9cf31a99c63a880596e68519999

doc/Type/Promise.pod6

@@ -81,8 +81,10 @@ thrown without any C<start> statement prefixes involved.
     =begin code
     use v6.d.PREVIEW;
     start { die }; sleep ⅓; say "hello";
-    # OUTPUT: Died
-    # in block  at -e line 1
+    # OUTPUT: 
+    # Unhandled exception in code scheduled on thread 4
+    # Died
+    #     in block  at -e line 1
     =end code
 
 If you wish to avoid this behaviour, use C<start> in non-sink context or
@@ -99,9 +101,10 @@ catch the exception yourself:
     # OUTPUT: «caught␤hello␤»
     =end code
 
-This behaviour exists only syntaxically and not as part of method L<sink>
-on L<Promise> object, thus sinking a L<Promise> object or having a C<start>
-block as return value of a routine won't trigger this behaviour.
+This behaviour exists only syntaxically, by using an alternate C<.sink> method
+for L<Promise> objects created by C<start> blocks in sink context, thus simply
+sinking a L<Promise> object that was created by other means won't trigger this
+behaviour.
 
 =head2 method in