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

@@ -49,12 +49,12 @@ dataset_info:
     dtype: string
   config_name: clean
   splits:
-  - name: test
-    num_bytes: 65784
-    num_examples: 100
   - name: train
     num_bytes: 1002365
     num_examples: 1813
+  - name: test
+    num_bytes: 65784
+    num_examples: 100
   download_size: 1192302846
   dataset_size: 1068149
 ---