Update taxonomy.json

taxonomy.json

@@ -254,10 +254,9 @@
          {"name": "Text Style Transfer"},
          {"name": "Text Simplification"},
          {"name": "Data-to-Text Generation",
-         "children": [
+           "children": [
              {"name": "Table-to-Text Generation"}
              ]
-         }
     },
     {
         "name": "Data Management and Generation",