[ao] adding note about warning to static quant tutorial (#2705)

* adding warning to quantization tutorial

Summary: users reported seeing a warning when running a tutorial, add a
comment calling this out as expected.
---------

Co-authored-by: Svetlana Karslioglu <svekars@meta.com>

Author: HDCharles

advanced_source/static_quantization_tutorial.rst

@@ -435,6 +435,9 @@ values to floats - and then back to ints - between every operation, resulting in
 
     # Convert to quantized model  
     torch.ao.quantization.convert(myModel, inplace=True)
+    # You may see a user warning about needing to calibrate the model. This warning can be safely ignored.
+    # This warning occurs because not all modules are run in each model runs, so some
+    # modules may not be calibrated.
     print('Post Training Quantization: Convert done') 
     print('\n Inverted Residual Block: After fusion and quantization, note fused modules: \n\n',myModel.features[1].conv)