Update dataset_info.json

Added the Nectar dataset already preprocessed and divided in sft and rl to which I added a preprompt to each instruction since it has been seen that this increase instruction following

data/dataset_info.json

@@ -266,6 +266,12 @@
     "columns": {
       "prompt": "content"
     }
+  "nectar_rlaif": {
+    "hf_hub_url": "mlinmg/RLAIF-Nectar",
+    "ranking": true
+  },
+  "nectar_sft": {
+    "hf_hub_url": "mlinmg/SFT-Nectar"
   },
   "starcoder": {
     "hf_hub_url": "bigcode/starcoderdata",