Add a note about list operator flattening.

S07-glr-draft.pod

@@ -88,6 +88,8 @@ Flattening also occurs using the C<flat> contextualizer:
 Slurpy array parameters declared with a single C<*> marker lazily 
 flatten the arguments into the array.
 
+List operators such as reduce, cross, and zip flatten their arguments.
+
 Conjecture:  An array constructor preceded by a colon flattens its
 interior contents.  Array constructors without the colon do not flatten
 the interior.
@@ -287,6 +289,7 @@ Some miscellaneous notes on list-based methods:
    @list.list           # may return self
    @list.kv             # returns (0, @list[0], 1, @list[1], ...)
                         # not ( (0, @list[0]), (1, @list[1]), ...)
+   infix:<Z>            # flattens its arguments
 
 =item *