Add comments to 3 functions in funkin.Assets

source/funkin/Assets.hx

@@ -144,16 +144,31 @@ class Assets
     return openfl.utils.Assets.list(type);
   }
 
+  /**
+   * Checks if a library with the given name exists.
+   * @param name The name to check.
+   * @return Whether or not the library exists.
+   */
   public static function hasLibrary(name:String):Bool
   {
     return openfl.utils.Assets.hasLibrary(name);
   }
 
+  /**
+   * Retrieves a library with the given name.
+   * @param name The name of the library to get.
+   * @return The library with the given name.
+   */
   public static function getLibrary(name:String):lime.utils.AssetLibrary
   {
     return openfl.utils.Assets.getLibrary(name);
   }
 
+  /**
+   * Loads a library with the given name.
+   * @param name The name of the library to load.
+   * @return An `AssetLibary` object.
+   */
   public static function loadLibrary(name:String):Future<openfl.utils.AssetLibrary>
   {
     return openfl.utils.Assets.loadLibrary(name);