[commands] Mark CommandPtr class as [[nodiscard]] (#7803)

This has the same effect but makes it so any user code returning CommandPtr can't discard a returned command.

Signed-off-by: Eric Ward <ezeward4@gmail.com>

wpilibcExamples/src/main/cpp/examples/DriveDistanceOffboard/include/subsystems/DriveSubsystem.h

@@ -82,7 +82,6 @@ class DriveSubsystem : public frc2::SubsystemBase {
    * @param distance The distance to drive forward.
    * @return A command.
    */
-  [[nodiscard]]
   frc2::CommandPtr ProfiledDriveDistance(units::meter_t distance);
 
   /**
@@ -92,7 +91,6 @@ class DriveSubsystem : public frc2::SubsystemBase {
    * @param distance The distance to drive forward.
    * @return A command.
    */
-  [[nodiscard]]
   frc2::CommandPtr DynamicProfiledDriveDistance(units::meter_t distance);
 
  private:

wpilibcExamples/src/main/cpp/examples/RapidReactCommandBot/include/subsystems/Drive.h

@@ -28,7 +28,6 @@ class Drive : public frc2::SubsystemBase {
    * @param fwd the commanded forward movement
    * @param rot the commanded rotation
    */
-  [[nodiscard]]
   frc2::CommandPtr ArcadeDriveCommand(std::function<double()> fwd,
                                       std::function<double()> rot);
 
@@ -39,7 +38,6 @@ class Drive : public frc2::SubsystemBase {
    * @param distance The distance to drive forward in meters
    * @param speed The fraction of max speed at which to drive
    */
-  [[nodiscard]]
   frc2::CommandPtr DriveDistanceCommand(units::meter_t distance, double speed);
 
   /**
@@ -48,7 +46,6 @@ class Drive : public frc2::SubsystemBase {
    *
    * @param angle The angle to turn to
    */
-  [[nodiscard]]
   frc2::CommandPtr TurnToAngleCommand(units::degree_t angle);
 
  private:

wpilibcExamples/src/main/cpp/examples/RapidReactCommandBot/include/subsystems/Intake.h

@@ -19,11 +19,9 @@ class Intake : public frc2::SubsystemBase {
 
   /** Returns a command that deploys the intake, and then runs the intake motor
    * indefinitely. */
-  [[nodiscard]]
   frc2::CommandPtr IntakeCommand();
 
   /** Returns a command that turns off and retracts the intake. */
-  [[nodiscard]]
   frc2::CommandPtr RetractCommand();
 
  private:

wpilibcExamples/src/main/cpp/examples/RapidReactCommandBot/include/subsystems/Pneumatics.h

@@ -17,7 +17,6 @@ class Pneumatics : frc2::SubsystemBase {
  public:
   Pneumatics();
   /** Returns a command that disables the compressor indefinitely. */
-  [[nodiscard]]
   frc2::CommandPtr DisableCompressorCommand();
 
   /**

wpilibcExamples/src/main/cpp/examples/RapidReactCommandBot/include/subsystems/Shooter.h

@@ -28,7 +28,6 @@ class Shooter : public frc2::SubsystemBase {
    *
    * @param setpointRotationsPerSecond The desired shooter velocity
    */
-  [[nodiscard]]
   frc2::CommandPtr ShootCommand(units::turns_per_second_t setpoint);
 
  private:

wpilibcExamples/src/main/cpp/examples/RapidReactCommandBot/include/subsystems/Storage.h

@@ -16,7 +16,6 @@ class Storage : frc2::SubsystemBase {
  public:
   Storage();
   /** Returns a command that runs the storage motor indefinitely. */
-  [[nodiscard]]
   frc2::CommandPtr RunCommand();
 
   /** Whether the ball storage is full. */