Updated few links URLs in data_performance.ipynb

I have updated the links for routing directly to the mentioned section which was not working earlier. Also changed the code format of 2 words.

Author: RenuPatelGoogle

site/en/guide/data_performance.ipynb

@@ -275,7 +275,7 @@
         "### Prefetching\n",
         "\n",
         "Prefetching overlaps the preprocessing and model execution of a training step.\n",
-        "While the model is executing training step `s`, the input pipeline is reading the data for step `s+1`.\n",
+        "While the model is executing training `steps`, the input pipeline is reading the data for `steps+1`.\n",
         "Doing so reduces the step time to the maximum (as opposed to the sum) of the training and the time it takes to extract the data.\n",
         "\n",
         "The `tf.data` API provides the `tf.data.Dataset.prefetch` transformation.\n",
@@ -713,12 +713,12 @@
         "Here is a summary of the best practices for designing performant TensorFlow\n",
         "input pipelines:\n",
         "\n",
-        "*   [Use the `prefetch` transformation](#Pipelining) to overlap the work of a producer and consumer\n",
-        "*   [Parallelize the data reading transformation](#Parallelizing-data-extraction) using the `interleave` transformation\n",
-        "*   [Parallelize the `map` transformation](#Parallelizing-data-transformation) by setting the `num_parallel_calls` argument\n",
-        "*   [Use the `cache` transformation](#Caching) to cache data in memory during the first epoch\n",
-        "*   [Vectorize user-defined functions](#Map-and-batch) passed in to the `map` transformation\n",
-        "*   [Reduce memory usage](#Reducing-memory-footprint) when applying the `interleave`, `prefetch`, and `shuffle` transformations"
+        "*   [Use the `prefetch` transformation](#prefetching) to overlap the work of a producer and consumer\n",
+        "*   [Parallelize the data reading transformation](#parallelizing_data_extraction) using the `interleave` transformation\n",
+        "*   [Parallelize the `map` transformation](#parallelizing_data_transformation) by setting the `num_parallel_calls` argument\n",
+        "*   [Use the `cache` transformation](#caching) to cache data in memory during the first epoch\n",
+        "*   [Vectorize user-defined functions](#vectorizing_mapping) passed in to the `map` transformation\n",
+        "*   [Reduce memory usage](#reducing_memory_footprint) when applying the `interleave`, `prefetch`, and `shuffle` transformations"
       ]
     },
     {