Fix a typo in ExtensionTypes guide.

PiperOrigin-RevId: 404394145

Author: edloper

site/en/guide/extension_type.ipynb

@@ -155,7 +155,7 @@
         "* **while loops**: Extension types can be used as loop variables in `tf.while_loop`, and can be used as arguments and return values for the while-loop's body.\n",
         "* **conditionals**: Extension types can be conditionally selected using `tf.cond` and `tf.case`.\n",
         "* **py_function**: Extension types can be used as arguments and return values for the `func` argument to `tf.py_function`.\n",
-        "* **Tensor ops**: Extension types can extended to support most TensorFlow ops that accept Tensor inputs (e.g., `tf.matmul`, `tf.gather`, and `tf.reduce_sum`). See the \"*Dispatch*\" section below for more information.\n",
+        "* **Tensor ops**: Extension types can be extended to support most TensorFlow ops that accept Tensor inputs (e.g., `tf.matmul`, `tf.gather`, and `tf.reduce_sum`). See the \"*Dispatch*\" section below for more information.\n",
         "* **distribution strategy**: Extension types can be used as per-replica values.\n",
         "\n",
         "For more details, see the section on \"TensorFlow APIs that support ExtensionTypes\" below.\n"