clang-tidy: modernize-use-override (NFC)

Add NOLINT to CommandTestBase due to gmock not adding "override" keyword,
which causes warnings on clang.

hal/src/main/native/athena/Interrupts.cpp

@@ -24,7 +24,7 @@ namespace {
 // Safe thread to allow callbacks to run on their own thread
 class InterruptThread : public wpi::SafeThread {
  public:
-  void Main() {
+  void Main() override {
     std::unique_lock lock(m_mutex);
     while (m_active) {
       m_cond.wait(lock, [&] { return !m_active || m_notify; });

hal/src/main/native/cpp/jni/InterruptJNI.cpp

@@ -31,7 +31,7 @@ using namespace hal;
 // process, we will just ignore the redundant wakeup.
 class InterruptThreadJNI : public wpi::SafeThread {
  public:
-  void Main();
+  void Main() override;
 
   bool m_notify = false;
   uint32_t m_mask = 0;

hal/src/main/native/include/hal/handles/IndexedClassedHandleResource.h

@@ -49,7 +49,7 @@ class IndexedClassedHandleResource : public HandleBase {
   }
   std::shared_ptr<TStruct> Get(THandle handle);
   void Free(THandle handle);
-  void ResetHandles();
+  void ResetHandles() override;
 
  private:
   std::array<std::shared_ptr<TStruct>, size> m_structures;