fix(api/application): Update return type hint for activeDocument method

Update the return type hint for the activeDocument method to improve code clarity and maintainability.

Signed-off-by: longhao <hal.long@outlook.com>

photoshop/api/application.py

@@ -80,7 +80,7 @@ def layerSets(self) -> LayerSets:
         return LayerSets(self.app.LayerSets)
 
     @property
-    def activeDocument(self):
+    def activeDocument(self) -> Document:
         """The front-most documents.
 
         Setting this property is equivalent to clicking an