Dataset doc cleanup (#205)

* Update iris.rs

* Update mod.rs

* Update digits.rs

src/dataset/digits.rs

@@ -1,4 +1,4 @@
-//! # Optical Recognition of Handwritten Digits Data Set
+//! # Optical Recognition of Handwritten Digits Dataset
 //!
 //! | Number of Instances | Number of Attributes | Missing Values? | Associated Tasks: |
 //! |-|-|-|-|

src/dataset/iris.rs

@@ -1,4 +1,4 @@
-//! # The Iris Dataset flower
+//! # The Iris flower dataset
 //!
 //! | Number of Instances | Number of Attributes | Missing Values? | Associated Tasks: |
 //! |-|-|-|-|

src/dataset/mod.rs

@@ -1,6 +1,6 @@
 //! Datasets
 //!
-//! In this module you will find small datasets that are used in SmartCore for demonstration purpose mostly.
+//! In this module you will find small datasets that are used in SmartCore mostly for demonstration purposes.
 pub mod boston;
 pub mod breast_cancer;
 pub mod diabetes;