UI tutorials: Properly reference final project zips

FYI @GDquest :)

getting_started/step_by_step/ui_code_a_life_bar.rst

@@ -386,8 +386,8 @@ takes seven arguments:
 6. The type of the transition
 7. The easing to use in combination with the equation.
 
-The last two arguments combined correspond to an `easing
-equation <#>`__. This controls how the value evolves from the start to
+The last two arguments combined correspond to an easing
+equation. This controls how the value evolves from the start to
 the end point.
 
 Click the script icon next to the ``GUI`` node to open it again. The

getting_started/step_by_step/ui_game_user_interface.rst

@@ -613,7 +613,8 @@ to the top edge of the game window. Then resize the GUI to make it as
 small as possible vertically. Now you can see how the interface looks in
 the context of the game.
 
-Congratulations for getting to the end of this long tutorial!
+Congratulations for getting to the end of this long tutorial. You can
+find the final project here: :download:`ui_gui_design.zip <files/ui_gui_design.zip>`.
 
 .. figure:: ./img/ui_gui_design_final_result.png
 

getting_started/step_by_step/ui_main_menu.rst

@@ -269,8 +269,9 @@ press enter, the ``Separation`` property becomes active and Godot adds
 Without a single line of code, we have a precise and responsive main
 menu.
 
-Congratulations for getting there! You can download the `final
-menu <#>`__ to compare with your own. In the next tutorial, you'll
+Congratulations for getting there! You can download the final
+menu :download:`ui_main_menu_design.zip <files/ui_main_menu_design.zip>`
+to compare with your own. In the next tutorial, you'll
 create a Game User Interface with bars and item counters.
 
 Break down the UI mockup