Fix release notes for 2019-12-23

Author: yikei

articles/machine-learning/azure-machine-learning-release-notes.md

@@ -163,8 +163,7 @@ See [the list of known issues](resource-known-issues.md) to learn about known bu
     + Added CreatedBy information to Model and Service objects. May be accessed through <var>.created_by
     + Fixed ContainerImage.run(), which was not correctly setting up the Docker container's HTTP port.
     + Make `azureml-dataprep` optional for `az ml dataset register` cli command
-  + **azureml-dataprep**
-    + Fixed a bug where TabularDataset.to_pandas_dataframe would incorrectly fall back to an alternate reader and print out a warning.
+    + Fixed a bug where `TabularDataset.to_pandas_dataframe` would incorrectly fall back to an alternate reader and print out a warning.
   + **azureml-explain-model**
     + defer shap dependency to interpret-community from azureml-interpret
   + **azureml-pipeline-core**