Use static typing in all demos (#1063)

This leads to code that is easier to understand and runs
faster thanks to GDScript's typed instructions.

The untyped declaration warning is now enabled on all projects
where type hints were added. All projects currently run without
any untyped declration warnings.

Dodge the Creeps and Squash the Creeps demos intentionally don't
use type hints to match the documentation, where type hints haven't
been adopted yet (given its beginner focus).

2d/navigation/character.gd

@@ -1,11 +1,10 @@
 extends CharacterBody2D
 
+var movement_speed := 200.0
 
-var movement_speed: float = 200.0
 @onready var navigation_agent: NavigationAgent2D = $NavigationAgent2D
 
-
-func _ready():
+func _ready() -> void:
 	# These values need to be adjusted for the actor's speed
 	# and the navigation layout.
 	navigation_agent.path_desired_distance = 2.0
@@ -15,17 +14,18 @@ func _ready():
 
 # The "click" event is a custom input action defined in
 # Project > Project Settings > Input Map tab.
-func _unhandled_input(event):
+func _unhandled_input(event: InputEvent) -> void:
 	if not event.is_action_pressed("click"):
 		return
+
 	set_movement_target(get_global_mouse_position())
 
 
-func set_movement_target(movement_target: Vector2):
+func set_movement_target(movement_target: Vector2) -> void:
 	navigation_agent.target_position = movement_target
 
 
-func _physics_process(_delta):
+func _physics_process(_delta: float) -> void:
 	if navigation_agent.is_navigation_finished():
 		return
 

2d/navigation/project.godot

@@ -19,6 +19,10 @@ run/main_scene="res://navigation.tscn"
 config/features=PackedStringArray("4.2")
 config/icon="res://icon.webp"
 
+[debug]
+
+gdscript/warnings/untyped_declaration=1
+
 [display]
 
 window/size/viewport_width=800
@@ -33,6 +37,10 @@ click={
 ]
 }
 
+[physics]
+
+common/physics_ticks_per_second=120
+
 [rendering]
 
 renderer/rendering_method="gl_compatibility"