update class diagram

Author: rcannood

vignettes/diagrams/class_diagram.mmd

@@ -18,7 +18,7 @@ classDiagram
   class ZarrAnnData["ZarrAnnData (Planned)"] {
     init(zarrFile)
   }
-  class ReticulateAnnData["ReticulateAnnData (Planned)"] {
+  class ReticulateAnnData["ReticulateAnnData"] {
     init(ptr)
   }