Follow the GDScript style guide in every script

- Types on every parameter, return value and variable, and snake_case names
  (the player name limit is the constant MAX_NAME_LENGTH).
- Spelling fixes: *_triggered, character_selected, separator, caught_errors.
  The server's catched_errors key stays as the server sends it.
- Signals are connected with signal.connect() instead of by name.
- Code is ordered signals, constants, exported vars, vars, @onready vars,
  functions, with @onready on one line and two blank lines between functions.
- Every script starts with a ## description. Template comments, old LOC notes
  and commented-out code are gone, apart from the local play code.
- Lines are at most 100 characters, apart from the local play path.
- The screenshot tour turns off the blinking text cursor so pictures match.

volume_slider.gd

@@ -1,19 +1,24 @@
 class_name VolumeSlider
 extends HSlider
+## A slider that sets the volume of an audio bus.
 
-@export
-var audio_bus_name := "music"
+## The audio bus whose volume the slider sets.
 
-@onready
-var _bus: int 
+@export var audio_bus_name: String = "music"
 
-func _ready():
+var _bus: int
+
+
+func _ready() -> void:
 	_bus = AudioServer.get_bus_index(audio_bus_name)
 	value_changed.connect(_on_value_changed)
 	value = db_to_linear(AudioServer.get_bus_volume_db(_bus))
 
-func _on_value_changed(changed_value: float) -> void:
-	AudioServer.set_bus_volume_db(_bus, linear_to_db(changed_value))
 
+## Sets the bus volume to [param changed_value], from 0 (silent) to 1 (full).
 func change_volume(changed_value: float) -> void:
 	AudioServer.set_bus_volume_db(_bus, linear_to_db(changed_value))
+
+
+func _on_value_changed(changed_value: float) -> void:
+	AudioServer.set_bus_volume_db(_bus, linear_to_db(changed_value))