Add doc examples of writing parquet files using ArrowWriter

[alamb]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.
When people ask how to create a parquet file in Rust, I would like to point them at the docs for the arrow writer.
https://docs.rs/parquet/5.4.0/parquet/arrow/arrow_writer/index.html#

An example when this would be helpful is on apache/datafusion#1024: apache/datafusion#1024 (comment)

Describe the solution you'd like
I would like an example on https://docs.rs/parquet/5.4.0/parquet/arrow/index.html#example-of-reading-parquet-file-into-arrow-record-batch that shows how to write files. The existing example shows how to read such files.

[matthewmturner]

@alamb ill work on this