Fix doc for EpisodeData and StepData (#310)

Author: umutucak

docs/api/minari_dataset/episode_data.md

@@ -30,6 +30,10 @@
 
     Stacked actions taken in each episode step.
 
+.. autoattribute:: minari.EpisodeData.rewards
+
+    The ``reward`` value after each environment step.
+
 .. autoattribute:: minari.EpisodeData.terminations
 
     The ``terminated`` value after each environment step.

docs/api/minari_dataset/step_data.md

@@ -18,11 +18,15 @@
 
     The action performed by the agent on the environment.
 
-.. autoattribute:: minari.StepData.termination
+.. autoattribute:: minari.StepData.reward
+
+    The ``reward`` value returned by the environment after performing the action.
+
+.. autoattribute:: minari.StepData.terminated
 
     The ``terminated`` value returned by the environment after performing the action.
 
-.. autoattribute:: minari.StepData.truncation
+.. autoattribute:: minari.StepData.truncated
 
     The ``truncated`` value returned by the environment after performing the action.