[wpimath] Replace frc/EigenCore.h typedefs with Eigen's where possible (#5597)

wpimath/src/main/native/include/frc/estimator/MecanumDrivePoseEstimator.h

@@ -9,7 +9,6 @@
 #include <wpi/SymbolExports.h>
 #include <wpi/array.h>
 
-#include "frc/EigenCore.h"
 #include "frc/estimator/PoseEstimator.h"
 #include "frc/geometry/Pose2d.h"
 #include "frc/geometry/Rotation2d.h"

wpimath/src/main/native/include/frc/estimator/PoseEstimator.h

@@ -4,10 +4,10 @@
 
 #pragma once
 
+#include <Eigen/Core>
 #include <wpi/SymbolExports.h>
 #include <wpi/array.h>
 
-#include "frc/EigenCore.h"
 #include "frc/geometry/Pose2d.h"
 #include "frc/geometry/Rotation2d.h"
 #include "frc/interpolation/TimeInterpolatableBuffer.h"

wpimath/src/main/native/include/frc/estimator/PoseEstimator.inc

@@ -81,9 +81,9 @@ void PoseEstimator<WheelSpeeds, WheelPositions>::AddVisionMeasurement(
   // Step 3: We should not trust the twist entirely, so instead we scale this
   // twist by a Kalman gain matrix representing how much we trust vision
   // measurements compared to our current pose.
-  Vectord<3> k_times_twist =
+  Eigen::Vector3d k_times_twist =
       m_visionK *
-      Vectord<3>{twist.dx.value(), twist.dy.value(), twist.dtheta.value()};
+      Eigen::Vector3d{twist.dx.value(), twist.dy.value(), twist.dtheta.value()};
 
   // Step 4: Convert back to Twist2d
   Twist2d scaledTwist{units::meter_t{k_times_twist(0)},