ML taxi fare tutorial updates (#5898)

* Updated ML taxi fare tutorial

* Mention that the Score column is special

* Addressed feedback

* Addressed feedback

* Addressed feedback

Author: pkulikov

docs/machine-learning/tutorials/index.md

@@ -7,7 +7,7 @@ ms.date: 06/06/2018
 
 The following tutorials enable you to understand how to use [ML.NET](../index.md) to build custom machine learning solutions and integrate them into your .NET applications:
 
-* [Sentiment Analysis](sentiment-analysis.md): demonstrates how to apply a binary classification task using ML.NET.
-* [Taxi Fare Predictor](taxi-fare.md): demonstrates how to apply a regression task using ML.NET.
+* [Sentiment analysis](sentiment-analysis.md): demonstrates how to apply a binary classification task using ML.NET.
+* [Taxi fare predictor](taxi-fare.md): demonstrates how to apply a regression task using ML.NET.
 
 For more examples that use ML.NET, check the [dotnet/machinelearning-samples](https://github.com/dotnet/machinelearning-samples) GitHub repository.