Docs: In `GeoDataFrame().sjoin()`, explain the predicate argument options better

[DeflateAwning]

It would be helpful to have these predicate options explained (e.g., does "intersects" still evaluate to true if a Line is fully inside a Polygon and thus doesn't intersect the Polygon's border - the answer is ofc yes, but if you're new to GEOS, you may not know).

Perhaps an outlink to the GEOS docs would be the best solution. I, however, can't find that at the moment.

Link: https://oreilles.github.io/polars-st/api-reference/geodataframe/#polars_st.GeoDataFrameNameSpace.sjoin

This is an opportunity for improvement compared to GeoPandas' equivalent docs (which similarly has no descriptions).