move out of alpha tier

Author: IoannisPanagiotas

doc/modules/ROOT/pages/algorithms/centrality.adoc

@@ -15,9 +15,9 @@ The Neo4j GDS library includes the following centrality algorithms, grouped by q
 ** xref:algorithms/closeness-centrality.adoc[Closeness Centrality]
 ** xref:algorithms/degree-centrality.adoc[Degree Centrality]
 ** xref:algorithms/eigenvector-centrality.adoc[Eigenvector Centrality]
+** xref:algorithms/harmonic-centrality.adoc[Harmonic Centrality]
 ** xref:algorithms/page-rank.adoc[Page Rank]
 
 
 * Alpha
-** xref:algorithms/harmonic-centrality.adoc[Harmonic Centrality]
 ** xref:algorithms/hits.adoc[HITS]