Fixed some toUndirected proc tests

Co-Authored-By: Florentin Dörre <florentin.dorre@neotechnology.com>

Author: yuvalr1neo

algo/src/test/java/org/neo4j/gds/beta/undirected/ToUndirectedTest.java

@@ -223,4 +223,4 @@ void shouldLogProgress() {
             );
     }
 
-}
+}

doc/modules/ROOT/pages/operations-reference/graph-operation-references.adoc

@@ -59,6 +59,10 @@
 | `gds.beta.graph.export.csv`
 | `gds.beta.graph.export.csv.estimate`
 |xref:graph-catalog-relationship-ops.adoc#catalog-graph-stream-relationship-topology-example[Stream relationship topologies to the procedure caller] | `gds.beta.graph.relationships.stream`
+.2+<.^|Convert directed relationships to undirected
+| `gds.beta.graph.relationships.toUndirected`
+| `gds.beta.graph.relationships.toUndirected.estimate`
+
 |===