chore: expose Series.blob accessor docs (#1546)

* chore: expose blob docs

* include semantic and ai

* exclude sem and ai, already in frames

Author: GarrettWu

bigframes/operations/blob.py

@@ -36,6 +36,13 @@
 
 @log_adapter.class_logger
 class BlobAccessor(base.SeriesMethods):
+    """
+    Blob functions for Series and Index.
+
+    .. note::
+        BigFrames Blob is still under experiments. It may not work and subject to change in the future.
+    """
+
     def __init__(self, *args, **kwargs):
         if not bigframes.options.experiments.blob:
             raise NotImplementedError()

docs/reference/bigframes.pandas/series.rst

@@ -51,6 +51,14 @@ Struct handling
     :inherited-members:
     :undoc-members:
 
+Blob handling
+^^^^^^^^^^^^^
+
+.. automodule:: bigframes.operations.blob
+    :members:
+    :inherited-members:
+    :undoc-members:
+
 Plotting handling
 ^^^^^^^^^^^^^^^^^