[wpilib] Document simulation APIs (#3079)

- Remove sim checkstyle suppression
- Add [[nodiscard]] to C++ register callback functions
- Add a couple of missing sim functions

Co-authored-by: Peter Johnson <johnson.peter@gmail.com>
Co-authored-by: Starlight220 <yotamshlomi@gmail.com>

wpilibc/src/main/native/include/frc/simulation/AnalogEncoderSim.h

@@ -28,7 +28,7 @@ class AnalogEncoderSim {
   explicit AnalogEncoderSim(const AnalogEncoder& encoder);
 
   /**
-   * Set the position using an {@link Rotation2d}.
+   * Set the position using an Rotation2d.
    *
    * @param angle The angle.
    */
@@ -47,7 +47,7 @@ class AnalogEncoderSim {
   units::turn_t GetTurns();
 
   /**
-   * Get the position as a {@link Rotation2d}.
+   * Get the position as a Rotation2d.
    */
   Rotation2d GetPosition();