message: Update hooks.d.ts
diff: +/**
  + * A generic type for the Hook callback functions. The parameters differ,
  + * depending on the hook. When the callback returns false, no further callbacks
  + * are called, that are registered under the same Hook name or would be called
  + * for other types after this callback is run. In all other cases the hooks will
  + * be run.
  + * @param args The arguments passed to the callback
  + * @return Whether additional callbacks should be called after this
  + */
  +declare type HookCallback = (...args: any[]) => boolean | void
  +
  +/**
  + * A simple event framework used throughout Foundry Virtual Tabletop.
  + * When key actions or events occur, a "hook" is defined where user-defined callback functions can execute.
  + * This class manages the registration and execution of hooked callback functions.
  + */
  declare class Hooks {
  /**
  * Register a callback handler which should be triggered when a hook is triggered.
  *
  * @param hook The unique name of the hooked event
  * @param fn The callback function which should be triggered when the hook event occurs
  + * @return An ID number of the hooked function which can be used to turn off the hook later
  */
  - static on(hook: string, fn: Function): number;
  + static on(hook: string, fn: HookCallback): number;
  /**
  * Called during initialization of Foundry
  */
  - static on(hook: 'init', fn: Function): number;
  + static on(hook: 'init', fn: HookCallback): number;
  /**
  * Called during game setup
  */
  - static on(hook: 'setup', fn: Function): number;
  + static on(hook: 'setup', fn: HookCallback): number;
  /**
  * Called when Foundry is ready
  */
  - static on(hook: 'ready', fn: Function): number;
  + static on(hook: 'ready', fn: HookCallback): number;
  /**
  * Register a callback handler for an event which is only triggered once the first time the event occurs.
  @@ -28,31 +45,32 @@ declare class Hooks {
  *
  * @param hook The unique name of the hooked event
  * @param fn The callback function which should be triggered when the hook event occurs
  + * @return An ID number of the hooked function which can be used to turn off the hook later
  */
  - static once(hook: string, fn: Function): number;
  + static once(hook: string, fn: HookCallback): number;
  /**
  * Called once during initialization of Foundry
  */
  - static once(hook: 'init', fn: Function): number;
  + static once(hook: 'init', fn: HookCallback): number;
  /**
  * Called once during game setup
  */
  - static once(hook: 'setup', fn: Function): number;
  + static once(hook: 'setup', fn: HookCallback): number;
  /**
  * Called once when Foundry is ready
  */
  - static once(hook: 'ready', fn: Function): number;
  + static once(hook: 'ready', fn: HookCallback): number;
  /**
  * Unregister a callback handler for a particular hook event
  *
  * @param hook The unique name of the hooked event
  - * @param fn The function that should be removed from the set of hooked callbacks
  + * @param fn The function, or ID number for the function, that should be turned off
  */
  - static off(hook: string, fn: Function): void;
  + static off(hook: string, fn: number | HookCallback): void;
  /**
  * Call all hook listeners in the order in which they were registered
  @@ -61,8 +79,7 @@ declare class Hooks {
  * @param hook The hook being triggered
  * @param args Arguments passed to the hook callback functions
  */
  -
  - static callAll(hook: string, ...args: any[]): boolean;
  + static callAll(hook: string, ...args: any[]): boolean | void;
  /**
  * Call hook listeners in the order in which they were registered.
  