[llvm] Use std::nullopt instead of None in comments (NFC)

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/unittests/IR/MetadataTest.cpp b/llvm/unittests/IR/MetadataTest.cpp
index bdab1f6..3ffa456 100644
--- a/llvm/unittests/IR/MetadataTest.cpp
+++ b/llvm/unittests/IR/MetadataTest.cpp
@@ -1214,7 +1214,7 @@ TEST_F(DILocationTest, discriminatorSpecialCases) {
                         .value()
                         ->getDuplicationFactor());
 
-  // Check we return None for unencodable cases.
+  // Check we return std::nullopt for unencodable cases.
   EXPECT_EQ(std::nullopt, L4->cloneWithBaseDiscriminator(0x1000));
   EXPECT_EQ(std::nullopt, L4->cloneByMultiplyingDuplicationFactor(0x1000));
 }