FIX: Fixed comment

src/Neuron/NeuronLinear.h

@@ -46,8 +46,8 @@ public:
      * f(x) = b*x + a
      * @param[in] param_idx Index of the parameter to calculate derivative of
      * @return Partial derivative of the activation function according to the
-     * 'param_idx'-th parameter. For 'param_idx'=0 returns 'x', otherwise
-     * returns 1
+     * 'param_idx'-th parameter. For 'param_idx'=0 returns 1, for 'param_idx=1'
+     * return 'x' and otherwise returns 0.
      */
     double activation_function_get_partial_derivative(int param_idx) override;