[Support] Add some missing namespace closure comments. NFCI.

Fixes some clang-tidy warnings.

lib/Support/APFloat.cpp

@@ -3748,7 +3748,7 @@ namespace {
     exp += FirstSignificant;
     buffer.erase(&buffer[0], &buffer[FirstSignificant]);
   }
-}
+} // namespace
 
 void IEEEFloat::toString(SmallVectorImpl<char> &Str, unsigned FormatPrecision,
                          unsigned FormatMaxPadding, bool TruncateZero) const {
@@ -4777,7 +4777,7 @@ DoubleAPFloat frexp(const DoubleAPFloat &Arg, int &Exp,
   return DoubleAPFloat(semPPCDoubleDouble, std::move(First), std::move(Second));
 }
 
-} // End detail namespace
+} // namespace detail
 
 APFloat::Storage::Storage(IEEEFloat F, const fltSemantics &Semantics) {
   if (usesLayout<IEEEFloat>(Semantics)) {

lib/Support/ARMWinEH.cpp

@@ -31,7 +31,7 @@ std::pair<uint16_t, uint32_t> SavedRegisterMask(const RuntimeFunction &RF) {
 
   return std::make_pair(GPRMask, VFPMask);
 }
-}
-}
-}
+} // namespace WinEH
+} // namespace ARM
+} // namespace llvm
 

lib/Support/Allocator.cpp

@@ -26,7 +26,7 @@ void printBumpPtrAllocatorStats(unsigned NumSlabs, size_t BytesAllocated,
          << " (includes alignment, etc)\n";
 }
 
-} // End namespace detail.
+} // namespace detail
 
 void PrintRecyclerStats(size_t Size,
                         size_t Align,
@@ -36,4 +36,4 @@ void PrintRecyclerStats(size_t Size,
          << "Number of elements free for recycling: " << FreeListSize << '\n';
 }
 
-}
+} // namespace llvm

lib/Support/BinaryStreamRef.cpp

@@ -62,7 +62,7 @@ public:
 private:
   MutableBinaryByteStream BBS;
 };
-}
+} // namespace
 
 BinaryStreamRef::BinaryStreamRef(BinaryStream &Stream)
     : BinaryStreamRefBase(Stream) {}

lib/Support/BuryPointer.cpp

@@ -27,4 +27,4 @@ void BuryPointer(const void *Ptr) {
   GraveYard[Idx] = Ptr;
 }
 
-}
+} // namespace llvm

lib/Support/CrashRecoveryContext.cpp

@@ -82,7 +82,7 @@ public:
     // this occurs when using SEH on Windows with MSVC or clang-cl.
   }
 };
-}
+} // namespace
 
 static ManagedStatic<std::mutex> gCrashRecoveryContextMutex;
 static bool gCrashRecoveryEnabled = false;
@@ -485,7 +485,7 @@ struct RunSafelyOnThreadInfo {
   bool UseBackgroundPriority;
   bool Result;
 };
-}
+} // namespace
 
 static void RunSafelyOnThread_Dispatch(void *UserData) {
   RunSafelyOnThreadInfo *Info =

lib/Support/DAGDeltaAlgorithm.cpp

@@ -174,7 +174,7 @@ public:
       : DDAI(DDAI), Required(Required) {}
 };
 
-}
+} // namespace
 
 DAGDeltaAlgorithmImpl::DAGDeltaAlgorithmImpl(
     DAGDeltaAlgorithm &DDA, const changeset_ty &Changes,

lib/Support/Debug.cpp

@@ -109,7 +109,7 @@ struct DebugOnlyOpt {
   }
 };
 
-}
+} // namespace
 
 static DebugOnlyOpt DebugOnlyOptLoc;
 

lib/Support/DynamicLibrary.cpp

@@ -116,7 +116,7 @@ static llvm::ManagedStatic<llvm::StringMap<void *>> ExplicitSymbols;
 static llvm::ManagedStatic<DynamicLibrary::HandleSet> OpenedHandles;
 // Lock for ExplicitSymbols and OpenedHandles.
 static llvm::ManagedStatic<llvm::sys::SmartMutex<true>> SymbolsMutex;
-}
+} // namespace
 
 #ifdef _WIN32
 
@@ -136,7 +136,7 @@ namespace llvm {
 void *SearchForAddressOfSpecialSymbol(const char *SymbolName) {
   return DoSearch(SymbolName); // DynamicLibrary.inc
 }
-}
+} // namespace llvm
 
 void DynamicLibrary::AddSymbol(StringRef SymbolName, void *SymbolValue) {
   SmartScopedLock<true> Lock(*SymbolsMutex);

lib/Support/ItaniumManglingCanonicalizer.cpp

@@ -207,7 +207,7 @@ struct CanonicalizerAllocator::MakeNodeImpl<
 
 using CanonicalizingDemangler =
     itanium_demangle::ManglingParser<CanonicalizerAllocator>;
-}
+} // namespace
 
 struct ItaniumManglingCanonicalizer::Impl {
   CanonicalizingDemangler Demangler = {nullptr, nullptr};

lib/Support/MathExtras.cpp

@@ -28,4 +28,4 @@ namespace llvm {
   const float huge_valf = HUGE_VALF;
 #endif
 
-}
+} // namespace llvm

lib/Support/MemoryBuffer.cpp

@@ -67,7 +67,7 @@ struct NamedBufferAlloc {
   const Twine &Name;
   NamedBufferAlloc(const Twine &Name) : Name(Name) {}
 };
-}
+} // namespace
 
 void *operator new(size_t N, const NamedBufferAlloc &Alloc) {
   SmallString<256> NameBuf;
@@ -101,7 +101,7 @@ public:
     return MemoryBuffer::MemoryBuffer_Malloc;
   }
 };
-}
+} // namespace
 
 template <typename MB>
 static ErrorOr<std::unique_ptr<MB>>
@@ -219,7 +219,7 @@ public:
     return MemoryBuffer::MemoryBuffer_MMap;
   }
 };
-}
+} // namespace
 
 static ErrorOr<std::unique_ptr<WritableMemoryBuffer>>
 getMemoryBufferForStream(sys::fs::file_t FD, const Twine &BufferName) {

lib/Support/PrettyStackTrace.cpp

@@ -73,7 +73,7 @@ PrettyStackTraceEntry *ReverseStackTrace(PrettyStackTraceEntry *Head) {
         std::make_tuple(Head, Head->NextEntry, Prev);
   return Prev;
 }
-}
+} // namespace llvm
 
 static void PrintStack(raw_ostream &OS) {
   // Print out the stack in reverse order. To avoid recursion (which is likely