clang-tidy: add ending namespace comments

Found with google-readability-namespace-comments

Signed-off-by: Rosen Penev <rosenp@gmail.com>

taglib/mpeg/id3v1/id3v1genres.cpp

@@ -224,7 +224,7 @@ namespace
     L"Psybient"
   };
   const int genresSize = sizeof(genres) / sizeof(genres[0]);
-}
+}  // namespace
 
 StringList ID3v1::genreList()
 {

taglib/mpeg/id3v2/frames/tableofcontentsframe.cpp

@@ -75,7 +75,7 @@ namespace {
     }
     return l;
   }
-}
+}  // namespace
 
 ////////////////////////////////////////////////////////////////////////////////
 // public methods

taglib/mpeg/id3v2/frames/textidentificationframe.cpp

@@ -133,7 +133,7 @@ namespace
       {"MIX", "MIXER"},
   };
   const size_t involvedPeopleSize = sizeof(involvedPeople) / sizeof(involvedPeople[0]);
-}
+}  // namespace
 
 const KeyConversionMap &TextIdentificationFrame::involvedPeopleMap() // static
 {

taglib/mpeg/id3v2/id3v2frame.cpp

@@ -74,7 +74,7 @@ namespace
     }
     return true;
   }
-}
+}  // namespace
 
 ////////////////////////////////////////////////////////////////////////////////
 // static methods
@@ -426,7 +426,7 @@ namespace
     {"TIME", "TDRC"}, // 2.3 -> 2.4
   };
   const size_t deprecatedFramesSize = sizeof(deprecatedFrames) / sizeof(deprecatedFrames[0]);
-}
+}  // namespace
 
 String Frame::frameIDToKey(const ByteVector &id)
 {

taglib/mpeg/id3v2/id3v2framefactory.cpp

@@ -85,7 +85,7 @@ namespace
 
     frame->setText(newfields);
   }
-}
+}  // namespace
 
 class FrameFactory::FrameFactoryPrivate
 {
@@ -477,7 +477,7 @@ namespace
     { "IPLS", "TIPL" },
   };
   const size_t frameConversion3Size = sizeof(frameConversion3) / sizeof(frameConversion3[0]);
-}
+}  // namespace
 
 bool FrameFactory::updateFrame(Frame::Header *header) const
 {

taglib/mpeg/id3v2/id3v2tag.cpp

@@ -64,7 +64,7 @@ namespace
     }
     return false;
   }
-}
+}  // namespace
 
 class ID3v2::Tag::TagPrivate
 {

taglib/mpeg/mpegfile.cpp

@@ -93,7 +93,7 @@ namespace
     AudioProperties *audioProperties() const { return 0; }
     bool save() { return false; }
   };
-}
+}  // namespace
 
 bool MPEG::File::isSupported(IOStream *stream)
 {