Update metadata on flat distributions

Author: Ostrzyciel

src/metadata.ttl

@@ -806,8 +806,8 @@ rb:TopicStreamElementSplit rdf:type owl:Class ;
 ###  https://w3id.org/riverbench/schema/metadata#flatDistribution
 rb:flatDistribution rdf:type owl:NamedIndividual ,
                              rb:DistributionType ;
-                    rdfs:comment "The dataset is distributed as a single flat file."@en ;
-                    rdfs:label "Flat distribution"@en .
+                    rdfs:comment "The dataset is distributed as a single flat file, using the RDF Message Log format."@en ;
+                    rdfs:label "Flat distribution (RDF Messages)"@en .
 
 
 ###  https://w3id.org/riverbench/schema/metadata#fullDistribution