doc: update from_dataframe docstring for clarity on DataFrame types and conversion

Author: kosiew

python/datafusion/table_provider.py

@@ -58,11 +58,12 @@ def from_dataframe(cls, df: Any) -> TableProvider:
         Parameters
         ----------
         df:
-            Either a :class:`~datafusion.dataframe.DataFrame` instance or a
-            DataFrame convertible via the Arrow FFI (for example,
-            :class:`pandas.DataFrame` or :class:`polars.DataFrame`). When you
-            already have a DataFusion DataFrame prefer calling
-            :meth:`~datafusion.dataframe.DataFrame.into_view` directly.
+            Either a :class:`~datafusion.dataframe.DataFrame` wrapper or the
+            corresponding :class:`~datafusion._internal.DataFrame`. When
+            working with third-party DataFrame libraries, convert them via
+            :meth:`~datafusion.SessionContext.from_arrow` before calling
+            :meth:`~datafusion.dataframe.DataFrame.into_view` or this
+            constructor.
         """
         from datafusion.dataframe import DataFrame as DataFrameWrapper