Reorder split names

Reorder split names in the YAML metadata to be aligned with the order in the loading script.
See: https://github.com/huggingface/datasets/issues/5258

README.md

@@ -341,12 +341,12 @@ dataset_info:
   - name: train
     num_bytes: 15508110
     num_examples: 10142
-  - name: trial
-    num_bytes: 1606931
-    num_examples: 1002
   - name: validation
     num_bytes: 5183809
     num_examples: 3219
+  - name: trial
+    num_bytes: 1606931
+    num_examples: 1002
   download_size: 3405146
   dataset_size: 25410916
 - config_name: drcd