Fix TPU Research Cloud link in TPU guide

Author: 8bitmp3

site/en/guide/tpu.ipynb

@@ -555,7 +555,7 @@
         "- [Google Cloud TPU performance guide](https://cloud.google.com/tpu/docs/performance-guide): Enhance Cloud TPU performance further by adjusting Cloud TPU configuration parameters for your application\n",
         "- [Distributed training with TensorFlow](./distributed_training.ipynb): How to use distribution strategies—including `tf.distribute.TPUStrategy`—with examples showing best practices.\n",
         "- TPU embeddings: TensorFlow includes specialized support for training embeddings on TPUs via `tf.tpu.experimental.embedding`. In addition, [TensorFlow Recommenders](https://www.tensorflow.org/recommenders) has `tfrs.layers.embedding.TPUEmbedding`. Embeddings provide efficient and dense representations, capturing complex similarities and relationships between features. TensorFlow's TPU-specific embedding support allows you to train embeddings that are larger than the memory of a single TPU device, and to use sparse and ragged inputs on TPUs.\n",
-        "- [TPU Research Cloud (TRC)] (https://sites.research.google/trc/about/): TRC enables researchers to apply for access to a cluster of more than 1,000 Cloud TPU devices.\n"
+        "- [TPU Research Cloud (TRC)](https://sites.research.google/trc/about/): TRC enables researchers to apply for access to a cluster of more than 1,000 Cloud TPU devices.\n"
       ]
     }
   ],