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

@@ -94,12 +94,12 @@ dataset_info:
     dtype: string
   config_name: yahoo_answers_topics
   splits:
-  - name: test
-    num_bytes: 32661362
-    num_examples: 60000
   - name: train
     num_bytes: 760460695
     num_examples: 1400000
+  - name: test
+    num_bytes: 32661362
+    num_examples: 60000
   download_size: 319476345
   dataset_size: 793122057
 ---