Standardize section headers for 03_activations module

modules/source/03_activations/activations_dev.py

@@ -224,6 +224,11 @@ class ReLU:
         """Make the class callable: relu(x) instead of relu.forward(x)"""
         return self.forward(x)
 
+# %% [markdown]
+"""
+## 🔧 DEVELOPMENT
+"""
+
 # %% [markdown]
 """
 ### 🧪 Test Your ReLU Implementation