[command] Rename PerpetualCommand to EndlessCommand (#4177)

wpilibNewCommands/src/main/native/cpp/frc2/command/EndlessCommand.cpp

@@ -0,0 +1,32 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#include "frc2/command/EndlessCommand.h"
+
+using namespace frc2;
+
+EndlessCommand::EndlessCommand(std::unique_ptr<Command>&& command) {
+  if (!CommandGroupBase::RequireUngrouped(*command)) {
+    return;
+  }
+  m_command = std::move(command);
+  m_command->SetGrouped(true);
+  AddRequirements(m_command->GetRequirements());
+}
+
+void EndlessCommand::Initialize() {
+  m_command->Initialize();
+}
+
+void EndlessCommand::Execute() {
+  m_command->Execute();
+}
+
+void EndlessCommand::End(bool interrupted) {
+  m_command->End(interrupted);
+}
+
+EndlessCommand EndlessCommand::Endlessly() && {
+  return std::move(*this);
+}