Partial Backport PR #44529 (#44556)

Author: simonjayhawkins

doc/source/user_guide/io.rst

@@ -2977,6 +2977,7 @@ Read in the content of the "books.xml" as instance of ``StringIO`` or
 Even read XML from AWS S3 buckets such as Python Software Foundation's IRS 990 Form:
 
 .. ipython:: python
+   :okwarning:
 
    df = pd.read_xml(
        "s3://irs-form-990/201923199349319487_public.xml",