* Add childStorageKeyPrefix to type-storage package * WIP * fix failing build * wrap StorageKey * no new line * Added childStoragePrefix param * Add childStorageKey param * Tests for child methods * Finalized tests * linting * Changed get_keys test to :code * Alphabetical imports * store hex values in consts * follow substrate order & empty line fixes * alphabetical export * Correct hex value for :child_storage: