removed nested columns

easier analysis of fields, also fix url_64kb to include full path

README.md

@@ -107,16 +107,18 @@ dataset_info:
     dtype: string
   - name: section_title
     dtype: string
+  - name: section_num
+    dtype: int32
   - name: reader_name
     dtype: string
   - name: url_64kb
     dtype: string
   splits:
   - name: train
-    num_bytes: 121525905
+    num_bytes: 123168741
     num_examples: 410709
-  download_size: 23364291
-  dataset_size: 121525905
+  download_size: 23841736
+  dataset_size: 123168741
 configs:
 - config_name: default
   data_files:

data/train-00000-of-00002.parquet

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:0db9892de76c254d9ae99a8bbe00947bf97242c7b79b669ea38a370b393e71f3
-size 12515479
+oid sha256:c5d8335b05a8112d09b76554402be16e6ace44fdfbfa3b15c04e0ee9f7c5fffa
+size 12750342

data/train-00001-of-00002.parquet

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:3f48232e05aaf5567c42051f6054727e6fda90a99b1ba71c8d2ad277a2e1b59a
-size 10848812
+oid sha256:b98eec5f8bedc4c73e35ec8a2e908bf9a87b8684465a00210ddb7bb2e912c2b5
+size 11091394