Update C++ API doc (#3671)

docs/source/index.rst

@@ -125,9 +125,9 @@ model implementations and application components.
    :caption: C++ Prototype API Reference
    :hidden:
 
-   libtorchaudio
-   libtorchaudio.stream_reader
-   libtorchaudio.stream_writer
+   libtorio
+   libtorio.stream_reader
+   libtorio.stream_writer
 
 .. toctree::
    :maxdepth: 1

docs/source/libtorchaudio.rst → docs/source/libtorio.rst

-libtorchaudio
-=============
+libtorio
+========
 
 .. warning::
    TorchAudio's C++ API is a prototype feature.
    API/ABI backward compatibility is not guaranteed.
 
 .. toctree::
-   libtorchaudio.stream_reader
-   libtorchaudio.stream_writer
+   libtorio.stream_reader
+   libtorio.stream_writer

docs/source/libtorchaudio.stream_reader.rst → docs/source/libtorio.stream_reader.rst

@@ -2,6 +2,11 @@
    TorchAudio's C++ API is a prototype feature.
    API/ABI backward compatibility is not guaranteed.
 
+
+.. note::
+   The top-level namespace has been changed from ``torchaudio`` to ``torio``.
+
+
 torio::io::StreamReader
 =======================
 

docs/source/libtorchaudio.stream_writer.rst → docs/source/libtorio.stream_writer.rst

@@ -2,6 +2,11 @@
    TorchAudio's C++ API is prototype feature.
    API/ABI backward compatibility is not guaranteed.
 
+
+.. note::
+   The top-level namespace has been changed from ``torchaudio`` to ``torio``.
+
+
 torio::io::StreamWriter
 =======================