docs(cache): Add new typedef for returned cache

- Declared a new typedef, `ExtractedVideoInfoCacheObject`, to represents the parsed and extracted cache of video information object
- Changed the returned type in `getCache` and `getAllCaches` functions

lib/cache.js

@@ -56,9 +56,21 @@
  * @property {string} authorName - The name of the author of the video or `'<unknown>'` if not available.
  * @property {string} videoUrl - The URL of the video.
  * @property {string} authorUrl - The URL of the author of the video (refers to author profile).
- * @property {Object} videoInfo - The video information object.
+ * @property {Object} videoInfo - The sealed video information object.
  * @property {'zlib/bin'} videoInfo.type - The type of the video information.
- * @property {ytdl.videoInfo} videoInfo.data - The video information data.
+ * @property {string} videoInfo.data - The compressed and binary encoded video information data.
+ * @global
+ * @since    2.0.0
+ */
+
+/**
+ * @typedef  {Object} ExtractedVideoInfoCacheObject
+ * @property {string} id - The ID of the video.
+ * @property {string} title - The title of the video or `'<unknown>'` if not available.
+ * @property {string} authorName - The name of the author of the video or `'<unknown>'` if not available.
+ * @property {string} videoUrl - The URL of the video.
+ * @property {string} authorUrl - The URL of the author of the video (refers to author profile).
+ * @property {ytdl.videoInfo} videoInfo - The extracted and unsealed video information object.
  * @global
  * @since    2.0.0
  */
@@ -377,7 +389,7 @@ class VInfoCache {
    *                                                 for checking the stored cache information.
    * @param {boolean} [cacheOptions.validate] - Whether to validate the cache object before returning it.
    *
-   * @returns {Promise.<VideoInfoCacheObject | string | null>}
+   * @returns {Promise.<ExtractedVideoInfoCacheObject | string | null>}
    *          A promise that resolves to the cached video information object, a cache formatted into a simple human-readable string
    *          if the `cacheOptions.humanReadable` option is enabled, or `null` if the cache does not exist.
    *
@@ -479,7 +491,7 @@ class VInfoCache {
    *                                                 for checking the stored cache information.
    * @param {boolean} [cacheOptions.validate] - Whether to validate for each cache object.
    *
-   * @returns {Promise.<Array.<VideoInfoCacheObject> | string>}
+   * @returns {Promise.<Array.<ExtractedVideoInfoCacheObject> | string>}
    *          A promise that resolves to an array of cache contents, a cache formatted into a simple human-readable string
    *          if the `cacheOptions.humanReadable` option is enabled, or an empty array if no caches are found.
    *