Standardize section headers for 11_training module

modules/source/11_training/training_dev.py

@@ -200,6 +200,11 @@ class MeanSquaredError:
         """Alternative interface for forward pass."""
         return self.__call__(y_pred, y_true)
 
+# %% [markdown]
+"""
+## 🔧 DEVELOPMENT
+"""
+
 # %% [markdown]
 """
 ### 🧪 Unit Test: MSE Loss