chore: updates docs

Author: OctoD

docs/how-to/apply_damage.md

@@ -26,10 +26,17 @@ extends AttributeBuff
 
 @export var damage: float = 1.0
 
-func _ready(_damage: float):
-    attribute_name = HealthAttribute.ATTRIBUTE_NAME
-    damage = _damage
-    operation = AttributeOperation.sub(damage)
+
+func _init(damage: float):
+  self.damage = damage
+
+
+func _apply(context: AttributeBuffContext) -> void:
+  var changeset = context.new_changeset()
+  
+  changeset.operate(context.get_attribute(HealthAttribute.ATTRIBUTE_NAME), AttributeOperation.subtract(damage))
+  
+  context.commit(changeset)
 ```
 
 Apply the buff to the `HealthAttribute` attribute like this:
@@ -39,24 +46,3 @@ attribute_container.apply_buff(DamageBuff.new(10.0))
 ```
 
 That's all folks!
-
-## Example 2, the complex way
-
-In certain games, you have multiple damage types, multiple resistances,
-and multiple damage sources.
-
-The logic (to handle the most complex cases) could sound awkward:
-- you have to create, for each damage type you need, a damage attribute
-- you have to assign these attributes to any attribute set you need (player, mobs, etc.). 
-- you must not deal with damage directly to the health, instead you have to increase the damage attributes
-- once an attribute changed, the [`AttributeContainer`](../classes/AttributeContainer.md) emits a `attribute_changed` signal.
-- if the attribute changed is a damage attribute, you should apply a new attribute buff
-  which is going to take care of calculating the proper damage, operating on health attribute and resetting the damage attribute(s) to 0.0.
-
-## Example 2.1, a complex but less complex way
-
-As the example above, but instead of handling damage as attributes, you
-can export the damage type(s) and value(s) as a resource.
-Once the buff
-is applied, take those into consideration to determine how the buff can damage the health attribute.
-