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

@@ -59,15 +59,15 @@ dataset_info:
       sequence: int32
   config_name: plain_text
   splits:
-  - name: test
-    num_bytes: 127640
-    num_examples: 38
   - name: train
     num_bytes: 1024378
     num_examples: 301
   - name: validation
     num_bytes: 125667
     num_examples: 38
+  - name: test
+    num_bytes: 127640
+    num_examples: 38
   download_size: 1927474
   dataset_size: 1277685
 ---