[wpimath] Use newer link to controls book in comments (NFC) (#2700)

wpimath/src/main/java/edu/wpi/first/wpilibj/estimator/KalmanFilter.java

@@ -29,7 +29,8 @@ import edu.wpi.first.wpiutil.math.numbers.N1;
  * the model.
  *
  * <p>For more on the underlying math, read
- * https://file.tavsys.net/control/controls-engineering-in-frc.pdf chapter 9.
+ * https://file.tavsys.net/control/controls-engineering-in-frc.pdf chapter 9 "Stochastic control
+ * theory".
  */
 @SuppressWarnings("ClassTypeParameterName")
 public class KalmanFilter<States extends Num, Inputs extends Num,

wpimath/src/main/java/edu/wpi/first/wpilibj/geometry/Pose2d.java

@@ -155,9 +155,9 @@ public class Pose2d {
   /**
    * Obtain a new Pose2d from a (constant curvature) velocity.
    *
-   * <p>See <a href="https://file.tavsys.net/control/state-space-guide.pdf">
-   * Controls Engineering in the FIRST Robotics Competition</a>
-   * section on nonlinear pose estimation for derivation.
+   * <p>See <a href="https://file.tavsys.net/control/controls-engineering-in-frc.pdf">
+   * Controls Engineering in the FIRST Robotics Competition</a> section 10.2 "Pose exponential" for
+   * a derivation.
    *
    * <p>The twist is a change in pose in the robot's coordinate frame since the
    * previous pose update. When the user runs exp() on the previous known

wpimath/src/main/java/edu/wpi/first/wpilibj/system/LinearSystemLoop.java

@@ -32,7 +32,7 @@ import edu.wpi.first.wpiutil.math.numbers.N1;
  * input because that's what comes back from the sensors).
  *
  * <p>For more on the underlying math, read
- * https://file.tavsys.net/control/state-space-guide.pdf.
+ * https://file.tavsys.net/control/controls-engineering-in-frc.pdf.
  */
 @SuppressWarnings("ClassTypeParameterName")
 public class LinearSystemLoop<States extends Num, Inputs extends Num,