DOC: temporary remove pyarrow example of reading subset columns (pandas-dev#18661)

Author: jorisvandenbossche

doc/source/io.rst

@@ -4601,7 +4601,6 @@ Read only certain columns of a parquet file.
 
 .. ipython:: python
 
-   result = pd.read_parquet('example_pa.parquet', engine='pyarrow', columns=['a', 'b'])
    result = pd.read_parquet('example_fp.parquet', engine='fastparquet', columns=['a', 'b'])
 
    result.dtypes