Typo fix in distribute_lib.

PiperOrigin-RevId: 338723266
Change-Id: I057cfce1f58c771570d8b1ff13785f7cc275ee67
diff --git a/tensorflow/python/distribute/distribute_lib.py b/tensorflow/python/distribute/distribute_lib.py
index de55b63..88d4d71 100644
--- a/tensorflow/python/distribute/distribute_lib.py
+++ b/tensorflow/python/distribute/distribute_lib.py
@@ -977,7 +977,7 @@
     }]
 
 
-    Three key actions happending under the hood of this method are batching,
+    Three key actions happening under the hood of this method are batching,
     sharding, and prefetching.
 
     In the code snippet above, `dataset` is batched by `global_batch_size`, and