[wpimath] Add ArmFeedforward calculate() overload that takes current and next velocity instead of acceleration (#6540)

Co-authored-by: Tyler Veness <calcmogul@gmail.com>

wpimath/src/main/java/edu/wpi/first/math/WPIMathJNI.java

@@ -44,6 +44,33 @@ public final class WPIMathJNI {
     libraryLoaded = true;
   }
 
+  // ArmFeedforward wrappers
+
+  /**
+   * Obtain a feedforward voltage from a single jointed arm feedforward object.
+   *
+   * <p>Constructs an ArmFeedforward object and runs its currentVelocity and nextVelocity overload
+   *
+   * @param ks The ArmFeedforward's static gain in volts.
+   * @param kv The ArmFeedforward's velocity gain in volt seconds per radian.
+   * @param ka The ArmFeedforward's acceleration gain in volt seconds² per radian.
+   * @param kg The ArmFeedforward's gravity gain in volts.
+   * @param currentAngle The current angle in the calculation in radians.
+   * @param currentVelocity The current velocity in the calculation in radians per second.
+   * @param nextVelocity The next velocity in the calculation in radians per second.
+   * @param dt The time between velocity setpoints in seconds.
+   * @return The calculated feedforward in volts.
+   */
+  public static native double calculate(
+      double ks,
+      double kv,
+      double ka,
+      double kg,
+      double currentAngle,
+      double currentVelocity,
+      double nextVelocity,
+      double dt);
+
   // DARE wrappers
 
   /**