Improve the message in Parquet conversion discussions
see https://huggingface.slack.com/archives/C02V51Q3800/p1707388935912969 (internal)

> Would it make sense to add some message in Parquet PRs (e.g. https://huggingface.co/datasets/huggan/smithsonian_butterflies_subset/discussions/2#65c41c1580497543ca3f8a5a) for less technical people?
> As an aside, I don't think the docs really mention the advantages of Parquet even if we link there for advantages (https://huggingface.co/docs/datasets-server/parquet)
> For example
> ```
> [bot] [No action needed] Conversion to Parquet
> 
> The parquet-converter bot has created a version of this dataset in the Parquet format in the `refs/convert/parquet` branch. This will allow X, Y, Z.
> 
> You can learn more about the advantages associated with this format in the documentation.
> ```

related to https://github.com/huggingface/datasets-server/issues/2349#issuecomment-1916292176

Improve the message in Parquet conversion discussions: see https://huggingface.slack.com/archives/C02V51Q3800/p1707388935912969 (internal)

> Would it make sense to add some message in Parquet PRs (e.g. https://huggingface.co/datasets/huggan/smithsonian_butterflies_subset/discussions/2#65c41c1580497543ca3f8a5a) for less technical people?
> As an aside, I don't think the docs really mention the advantages of Parquet even if we link there for advantages (https://huggingface.co/docs/datasets-server/parquet)
> For example
> ```
> [bot] [No action needed] Conversion to Parquet
> 
> The parquet-converter bot has created a version of this dataset in the Parquet format in the `refs/convert/parquet` branch. This will allow X, Y, Z.
> 
> You can learn more about the advantages associated with this format in the documentation.
> ```

related to https://github.com/huggingface/datasets-server/issues/2349#issuecomment-1916292176
