[TextAPI/MachO] Fix style issues. NFC

See https://llvm.org/docs/CodingStandards.html#use-namespace-qualifiers-to-implement-previously-declared-functions

llvm/lib/TextAPI/MachO/InterfaceFile.cpp

@@ -14,9 +14,10 @@
 #include <iomanip>
 #include <sstream>
 
-namespace llvm {
-namespace MachO {
-namespace detail {
+using namespace llvm;
+using namespace llvm::MachO;
+
+namespace {
 template <typename C>
 typename C::iterator addEntry(C &Container, StringRef InstallName) {
   auto I = partition_point(Container, [=](const InterfaceFileRef &O) {
@@ -39,21 +40,21 @@ typename C::iterator addEntry(C &Container, const Target &Target_) {
 
   return Container.insert(Iter, Target_);
 }
-} // end namespace detail.
+} // end namespace
 
 void InterfaceFileRef::addTarget(const Target &Target) {
-  detail::addEntry(Targets, Target);
+  addEntry(Targets, Target);
 }
 
 void InterfaceFile::addAllowableClient(StringRef InstallName,
                                        const Target &Target) {
-  auto Client = detail::addEntry(AllowableClients, InstallName);
+  auto Client = addEntry(AllowableClients, InstallName);
   Client->addTarget(Target);
 }
 
 void InterfaceFile::addReexportedLibrary(StringRef InstallName,
                                          const Target &Target) {
-  auto Lib = detail::addEntry(ReexportedLibraries, InstallName);
+  auto Lib = addEntry(ReexportedLibraries, InstallName);
   Lib->addTarget(Target);
 }
 
@@ -97,7 +98,7 @@ void InterfaceFile::addUUID(const Target &Target, uint8_t UUID[16]) {
 }
 
 void InterfaceFile::addTarget(const Target &Target) {
-  detail::addEntry(Targets, Target);
+  addEntry(Targets, Target);
 }
 
 InterfaceFile::const_filtered_target_range
@@ -118,6 +119,3 @@ void InterfaceFile::addSymbol(SymbolKind Kind, StringRef Name,
     for (const auto &Target : Targets)
       result.first->second->addTarget(Target);
 }
-
-} // end namespace MachO.
-} // end namespace llvm.

llvm/lib/TextAPI/MachO/TextStub.cpp

@@ -1089,8 +1089,8 @@ struct DocumentListTraits<std::vector<const MachO::InterfaceFile *>> {
 };
 
 } // end namespace yaml.
+} // namespace llvm
 
-namespace MachO {
 static void DiagHandler(const SMDiagnostic &Diag, void *Context) {
   auto *File = static_cast<TextAPIContext *>(Context);
   SmallString<1024> Message;
@@ -1147,6 +1147,3 @@ Error TextAPIWriter::writeToStream(raw_ostream &OS, const InterfaceFile &File) {
 
   return Error::success();
 }
-
-} // end namespace MachO.
-} // end namespace llvm.