added project.material doctest

added comments to documentation code example doctest, not sure how I feel about it

src/cript/nodes/primary_nodes/project.py

@@ -207,12 +207,14 @@ def material(self) -> List[Material]:
 
         Examples
         --------
-        ```python
-        identifier = [{"alternative_names": "my material alternative name"}]
-        my_material = cript.Material(name="my material", identifier=identifier)
-
-        my_project.material = [my_material]
-        ```
+        >>> import cript
+        >>> # create project node
+        >>> my_project = cript.Project(name="my Project name")
+        >>> # create material node
+        >>> identifier = [{"bigsmiles": "my big smiles"}]
+        >>> my_material = cript.Material(name="my material", identifier=identifier)
+        >>> # add material node to project node
+        >>> my_project.material = [my_material]
 
         Returns
         -------