Add lower bound restriction of shortestPath() and allShortestPath() to the rules section

Author: WilcoNeo

modules/ROOT/pages/patterns/reference.adoc

@@ -1415,7 +1415,7 @@ shortestPath((:A)-->+(:B))
 [[shortest-functions-rules-path-pattern-length]]
 ==== Path pattern length
 
-There must be exactly one relationship pattern in the path pattern.
+There must be exactly one relationship pattern in the path pattern, and the lower bound should be 0 or 1.
 
 .Allowed
 [source]
@@ -1428,6 +1428,8 @@ shortestPath((a)-[:R*1..5]-(b))
 ----
 shortestPath((a)-[:R*1..5]-(b)-->(:X))
 
+shortestPath((a)-[:R*2..5]-(b))
+
 shortestPath((:A))
 
 allShortestPaths((a:A)-[:S*]->(:B), (a)-[:R*1..3]->(:C))