update README.md

README.md

@@ -45,11 +45,11 @@ are Web pages from Common Crawl in Chinese, Persian, and Russian.
 
 ### Data Instances
 
-| Split          | Documents |
-|----------------|----------:|
-| `fa` (Persian) |      486K |
-| `ru` (Russian) |      4.7M |
-| `zh` (Chinese) |      646K |
+| Split           | Documents |
+|-----------------|----------:|
+| `fas` (Persian) |      486K |
+| `rus` (Russian) |      4.7M |
+| `zho` (Chinese) |      646K |
 
 ### Data Fields
  - `id`: unique identifier for this document