[DOC] add link to method in docstring of StreamFile

bob/io/stream/stream_file.py

@@ -10,7 +10,8 @@ from .config import load_data_config
 class StreamFile:
     """File class to read from HDF5 streams files.
 
-    Exposes methods to read a stream's data and meta-data.
+    Exposes methods to read a stream's data and meta-data. The class is initialized via 
+    :meth:`~bob.io.stream.StreamFile.set_source`.
 
     Attributes
     ----------