Update docstrings

Author: jpolchlo

pystac/extensions/raster.py

@@ -663,14 +663,17 @@ class RasterExtension(
     ExtensionManagementMixin[Union[pystac.Item, pystac.Collection]],
 ):
     """An abstract class that can be used to extend the properties of an
-    :class:`~pystac.Item` or :class:`~pystac.Asset` with properties from
+    :class:`~pystac.Item`, :class:`~pystac.Asset`, or
+    :class:`~pystac.extension.item_assets.AssetDefinition` with properties from
     the :stac-ext:`Raster Extension <raster>`. This class is generic over
     the type of STAC Object to be extended (e.g. :class:`~pystac.Item`,
     :class:`~pystac.Asset`).
 
     This class will generally not be used directly. Instead, use the concrete
     implementation associated with the STAC Object you want to extend (e.g.
-    :class:`~ItemRasterExtension` to extend an :class:`~pystac.Item`).
+    :class:`~ItemRasterExtension` to extend an :class:`~pystac.Item`).  You may
+    prefer to use the `ext` class method of this class to construct the correct
+    instance type for you.
     """
 
     properties: Dict[str, Any]
@@ -769,6 +772,8 @@ def __repr__(self) -> str:
 
 class ItemAssetsRasterExtension(RasterExtension[item_assets.AssetDefinition]):
     asset_defn: item_assets.AssetDefinition
+    """A reference to the :class:`~pystac.extensions.item_assets.AssetDefinition`
+    being extended."""
 
     properties: Dict[str, Any]
     """The :class:`~pystac.extensions.item_assets.AssetDefinition` fields, including