Fix missing descriptions.

src/main/resources/assets/nucleus/commands.properties

@@ -175,6 +175,10 @@ These flags are:\n\n\
 * -s/--seed <seed>: The seed to use to generate the world. If not specified, a random seed will be used.\n\n\
 The difficulty and the game mode can be changed after the world is generated.
 
+world.gamerule.desc=Displays a world''s game rules.
+
+world.gamerule.set.desc=Sets the specified world''s game rule.
+
 world.delete.desc=Deletes a world from the disc.
 world.delete.extended=This command irreversibly removes a world that has been unloaded and disabled from the disc. Before removal, the file path \
 will be shown to be checked before the removal is confirmed and completed.\n\