[llvm] [NFC][LLVM] Namespace cleanup in MetadataLoader.cpp (PR #157595)

[David Blaikie via llvm-commits]

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@@ -58,9 +58,6 @@
 #include <tuple>
 #include <utility>
 #include <vector>
-namespace llvm {
-class Argument;
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dwblaikie wrote:

This name is used in this file - so either the forward decl should remain, or the header that declares this should be included, right?

https://github.com/llvm/llvm-project/pull/157595