Add another criteria for when SHORTEST queries are rewritten with to use legacy operator (neo4j#1371)

Author: JPryce-Aklundh

modules/ROOT/pages/patterns/shortest-paths.adoc

@@ -846,6 +846,8 @@ Or, when the estimated cardinality of the source and target nodes in a shortest
 * Selector is one of: `SHORTEST 1`, `ANY`, `ANY SHORTEST`, `ALL SHORTEST`, `SHORTEST GROUP`, or `SHORTEST 1 GROUP`.
 * There is only one relationship pattern.
 * If the pattern is a xref:patterns/variable-length-patterns.adoc#quantified-path-patterns[quantified path pattern] in the form of `\(()-[]-())`, or is a  xref:patterns/variable-length-patterns.adoc#quantified-relationships[quantified-relationship], and it uses a filter that can be applied directly to the relationship.
+* If the pattern is a quantified path pattern or a quantified relationship and the relationship pattern is directed, the lower bound of the xref:patterns/reference.adoc#quantifiers[quantifier] is 0 or 1.
+If the relationship pattern is directed, the lower bound is 0.
 * In the case of a quantified path pattern, there are no node variables declared inside the quantified path pattern that are referenced elsewhere.
 
 | `StatefulShortestPath(Into)`