[llvm] [NFC][TableGen] Use namespace qualifier to define `RecordKeeperImpl` (PR #166220)

[Rahul Joshi via llvm-commits]

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@@ -46,12 +46,11 @@ using namespace llvm;
 //    Context
 //===----------------------------------------------------------------------===//
 
-namespace llvm::detail {
 /// This class represents the internal implementation of the RecordKeeper.
 /// It contains all of the contextual static state of the Record classes. It is
 /// kept out-of-line to simplify dependencies, and also make it easier for
 /// internal classes to access the uniquer state of the keeper.
-struct RecordKeeperImpl {
+struct detail::RecordKeeperImpl {
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jurahul wrote:

Yes.

https://github.com/llvm/llvm-project/pull/166220