DOC: Parquet IO docs don't match code

[mattayes]

Problem description

The Parquet section of the IO docs mentions the following caveat:

The format will NOT write an Index, or MultiIndex for the DataFrame and will raise an error if a non-default one is provided. You can simply .reset_index(drop=True) in order to store the index.

This conflicts with the error messages, which recommends:

you can .reset_index() to make the index into column(s)

Expected Output

AFAIK the error message is correct and the IO docs should remove drop=True:

The format will NOT write an Index, or MultiIndex for the DataFrame and will raise an error if a non-default one is provided. You can simply .reset_index() in order to store the index.

I'm happy to submit a PR for this.

[jorisvandenbossche]

Yes, the drop=True indeed seems incorrect if the goal is to store the index (or you could mention both options: drop=True to ignore the index). PR very welcome!