docs: Add polars-ds to list of community plugins (pola-rs#12527)

Co-authored-by: Stijn de Gooijer <[email protected]>

docs/user-guide/expressions/plugins.md

@@ -249,4 +249,5 @@ That's all you need to know to get started. Take a look at this [repo](https://g
 Here is a curated (non-exhaustive) list of community implemented plugins.
 
 - [polars-business](https://github.com/MarcoGorelli/polars-business) Polars extension offering utilities for business day operations
+- [polars-ds](https://github.com/abstractqqq/polars_ds_extension) Polars extension aiming to simplify common numerical/string data analysis procedures
 - [polars-hash](https://github.com/ion-elgreco/polars-hash) Stable non-cryptographic and cryptographic hashing functions for Polars