Prefer LinksByKey::link over LinksByKey::addReference

Pr/PrMCTools/src/PrLHCbID2MCParticle.cpp

@@ -108,9 +108,7 @@ namespace {
     } );
     // remove any possible duplicates
     partList.erase( std::unique( partList.begin(), partList.end() ), partList.end() );
-    for ( const auto& part : partList ) {
-      olink.addReference( id.lhcbID(), -1, part->index(), olink.linkID( &mcParts ), 1.0 );
-    }
+    for ( const auto& part : partList ) { olink.link( id.lhcbID(), mcParts( part->index() ), 1.0 ); }
   }
 
   /**