trajectory/ballistics/calculators/BCResult: Make into a record class

lib/src/main/java/org/fairportrobotics/frc/robolib/trajectory/ballistics/calculators/BCResult.java

@@ -2,19 +2,15 @@ package org.fairportrobotics.frc.robolib.trajectory.ballistics.calculators;
 
 import org.fairportrobotics.frc.robolib.trajectory.ballistics.constraints.BCEvalParams;
 
-public class BCResult {
-    public final Double         penalty;    /// The penalty for the computed launcher velocity (null if invalid)
-    public final BCEvalParams   evalParams; /// The BCEvalParams instance that produced the best penalty
-
-
-    public BCResult(
-        Double          penalty,
-        BCEvalParams    evalParams
-    ) {
-        this.penalty    = penalty;
-        this.evalParams = evalParams;
-    }
+/**
+ * Record type for ballistic calculator results
+ */
+public record BCResult(Double penalty, BCEvalParams evalParams) {
 
+    /**
+     * Checks if the result is valid (i.e. checks if penalty != null)
+     * @return True if the evalParams evaluates as valid, false otherwise
+     */
     public boolean isValid() {
         return this.penalty != null;
     }

lib/src/main/java/org/fairportrobotics/frc/robolib/trajectory/ballistics/calculators/HillDescentBallisticCalculator.java

@@ -45,7 +45,7 @@ public class HillDescentBallisticCalculator extends BallisticCalculator {
                 if(model.paramComputed(param)) continue;
 
                 BCResult result = this.evalSingleCandidate(model, param, robotVelocity, robotAngle, shooterVelocity);
-                if(result.penalty < bestResult.penalty) {
+                if(result.isValid() && result.penalty() < bestResult.penalty()) {
                     bestParam           = param;
                     bestResult          = result;
                     foundImprovement    = true;