Just a dot in order to be consistent (tensorflow#12919)

added a dot to the `7` to make clear it's a float (like every other number)

tensorflow/docs_src/get_started/get_started.md

@@ -447,7 +447,7 @@ estimator = tf.estimator.Estimator(model_fn=model_fn)
 x_train = np.array([1., 2., 3., 4.])
 y_train = np.array([0., -1., -2., -3.])
 x_eval = np.array([2., 5., 8., 1.])
-y_eval = np.array([-1.01, -4.1, -7, 0.])
+y_eval = np.array([-1.01, -4.1, -7., 0.])
 input_fn = tf.estimator.inputs.numpy_input_fn(
     {"x": x_train}, y_train, batch_size=4, num_epochs=None, shuffle=True)
 train_input_fn = tf.estimator.inputs.numpy_input_fn(