Tensor documentation update. (#263)

Resolves [TF-448](https://bugs.swift.org/browse/TF-448).

Author: ksasi

Sources/TensorFlow/Core/Tensor.swift

@@ -23,8 +23,11 @@ public protocol AnyTensor {
     var _tensorFlowDataType: TensorDataType { get }
 }
 
-/// `Tensor` is a multi-dimensional array used for computation. It is a wrapper around a
-/// `TensorHandle`.
+/// A multidimensional array of elements that is a generalization of vectors and matrices to 
+/// potentially higher dimensions.
+///
+/// The generic parameter `Scalar` describes the type of scalars in the tensor (such as `Int32`,
+///  `Float`, etc).
 @frozen
 public struct Tensor<Scalar: TensorFlowScalar>: TensorProtocol {
     /// The underlying `TensorHandle`.