Fix typo in Patterns reference (#1017)

Author: JPryce-Aklundh

modules/ROOT/pages/patterns/reference.adoc

@@ -779,7 +779,7 @@ Matches one or more relationships with type `R` and of any direction, and any no
 ()-[:R]-+()
 ----
 
-Matches paths consisting of two inbound subpaths, one with relationships of type `A` and one with relationships of type `B`, meeting at a node with label `A`:
+Matches paths consisting of two inbound subpaths, one with relationships of type `R` and one with relationships of type `S`, meeting at a node with label `A`:
 [source, role=noheader]
 ----
 ()-[:R]->+(:A)<-[:S]-+()