docs: fix InverseRelationShadowVariable code snippet (#1066)

InverseRelationShadowVariable is on a collection of the holder of the
relationship. For instance, see the `Consumer` to `Facility` in the
`facility-location` quickstart project.

docs/src/modules/ROOT/pages/using-timefold-solver/modeling-planning-problems.adoc

@@ -619,7 +619,7 @@ Java::
 public class Timeslot {
 
     @InverseRelationShadowVariable(sourceVariableName = "timeslot")
-    public List<Timeslot> timeslotList;
+    public List<Lesson> lessons;
 
     ...
 
@@ -632,7 +632,7 @@ Python::
 ----
 @planning_entity
 class Timeslot:
-    timeslot_list: Annotated[list[Timeslot], InverseRelationShadowVariable(source_variable_name ="timeslot")]
+    lesson_list: Annotated[list[Lesson], InverseRelationShadowVariable(source_variable_name ="timeslot")]
     ...
 ----
 ====
@@ -2791,4 +2791,4 @@ def generate_demo_data(demo_data: DemoData) -> Timetable:
 ====
 
 Usually, most of this data comes from your data layer,
-and your solution implementation just aggregates that data and creates the uninitialized planning entity instances for the solver to plan.
+and your solution implementation just aggregates that data and creates the uninitialized planning entity instances for the solver to plan.