Optimized item and background signal handling (#365)

Co-authored-by: Dennis Ploeger <develop@dieploegers.de>
Co-authored-by: dploeger <dploeger@users.noreply.github.com>

docs/api/ESCBackground.md

@@ -69,3 +69,5 @@ Texture or set size
 #### Parameters
 
 - position: The position where the player clicked
+- signal mouse_wheel_up(): Emitted when the mouse wheel was turned up
+- signal mouse_wheel_down(): Emitted when the mouse wheel was turned down

docs/api/ESCInputsManager.md

@@ -53,4 +53,21 @@ A LIFO stack of hovered items
 var hotspot_focused: String = ""
 ```
 
-The global id fo the topmost item from the hover_stack
+The global id fo the topmost item from the hover_stack
+
+## Method Descriptions
+
+### register\_inventory\_item
+
+```gdscript
+func register_inventory_item(item: Node)
+```
+
+Connect the item signals to the local methods
+
+### register\_background
+
+```gdscript
+func register_background(background: ESCBackground)
+```
+