Refactor mana regeneration to add flash effect callback

lib/spellbook.lua

@@ -99,8 +99,17 @@ function regenerateMana:cast(caster, target)
         Tree.behaviors.positioned.new(caster:has(Tree.behaviors.positioned).position + Vec3 { 0.5, 0.5 }),
     }
 
+    local flash = function(callback)
+        light:has(Tree.behaviors.light):animateColor(Vec3 {})(
+            function()
+                light:die()
+                callback()
+            end
+        )
+    end
+
     return task.wait {
-        light:has(Tree.behaviors.light):animateColor(Vec3 {}),
+        flash,
         sprite:animate("hurt")
     }
 end