c10::nullopt -> std::nullopt

Summary:
X-link: pytorch/torchrec#2515

X-link: pytorch/executorch#6461

X-link: pytorch/audio#3848

X-link: pytorch/ao#1151

X-link: facebookincubator/AITemplate#1032

Reviewed By: houseroad

Differential Revision: D64835967

fbshipit-source-id: 9f9f65335aaf5497680561027ef9314e4b36f8d9

torchcsprng/csrc/csprng.cpp

@@ -317,15 +317,15 @@ Tensor decrypt_pybind(Tensor input, Tensor output, Tensor key, const std::string
 
 // ====================================================================================================================
 
-Generator create_random_device_generator(std::optional<std::string> token = c10::nullopt) {
+Generator create_random_device_generator(std::optional<std::string> token = std::nullopt) {
   if (token.has_value()) {
     return make_generator<CSPRNGGeneratorImpl>(*token);
   } else {
     return make_generator<CSPRNGGeneratorImpl>(true);
   }
 }
 
-Generator create_mt19937_generator(std::optional<uint64_t> seed = c10::nullopt) {
+Generator create_mt19937_generator(std::optional<uint64_t> seed = std::nullopt) {
   if (seed.has_value()) {
     return make_generator<CSPRNGGeneratorImpl>(*seed);
   } else {