Update and clarify description of reduce on ops beginning with backslash

infix:<\x> was wrongly stated to completely mask triangle reduce with
infix:<x>, but we now have the [\[x]] syntax for disambiguation.

S03-operators.pod

@@ -4755,10 +4755,11 @@ list of lists, you can use a "triangular comma":
 If there is ambiguity between a triangular reduce and an infix operator
 beginning with backslash, the infix operator is chosen, and an extra backslash
 indicates the corresponding triangular reduce.  As a consequence, defining an
-infix operator beginning with backslash, C<< infix:<\x> >> say, will make it
-impossible to write certain triangular reduction operators, since C<[\x]> would
-mean the normal reduction of C<< infix:<\x> >> operator, not the triangular
-reduction of C<< infix:<x> >>.  This is deemed to be an insignificant problem.
+infix operator beginning with backslash, C<< infix:<\x> >> say, would cause
+C<[\x]> to mean the normal reduction of C<< infix:<\x> >>, not the triangular
+reduction of C<< infix:<x> >>.  To disambiguate, the syntax C<[\[x]]> can be
+used to reduce with C<< infix:<x> >>, while C<[\\x]> or C<[\[\x]]> could be
+used for triangular reduce with C<< infix:<\x> >>.
 
 Triangular reductions of chaining operators always consist of one or
 more C<True> values followed by 0 or more C<False> values.