docs: updated cwd, watch & callbacks inline documentation

Author: shakyShane

lib/default-config.js

@@ -3,13 +3,6 @@
  */
 module.exports = {
 
-    /**
-     * Current working directory
-     * @property cwd
-     * @type String
-     * @since 2.23.0
-     */
-
     /**
      * Browsersync includes a user-interface that is accessed via a separate port.
      * The UI allows to controls all devices, push sync updates and much more.
@@ -44,7 +37,11 @@ module.exports = {
     watchEvents: ["change"],
 
     /**
-     * Watch files automatically
+     * Watch files automatically - this should be used as an
+     * alternative to the `files` option. When this option is used, some directories
+     * will be ignored automatically such as `node_modules` `bower_components` `.sass-cache`
+     * `.vscode` `.git` `.idea`
+     *
      * @property watch
      * @type Boolean
      * @default false
@@ -173,6 +170,25 @@ module.exports = {
      * @since 2.18.0
      */
 
+    /**
+     * Current working directory
+     * @property cwd
+     * @type String
+     * @since 2.23.0
+     */
+
+    /**
+     * Register callbacks via a regular option - this can be used
+     * to get access the Browsersync instance in situations where you
+     * cannot provide a callback via the normal API (for example, in a Gruntfile)
+     *
+     * **Note**: Only the `ready` callback is currently supported here.
+     *
+     * @property callbacks
+     * @type Object
+     * @param {Function} ready
+     */
+
     /**
      * Clicks, Scrolls & Form inputs on any device will be mirrored to all others.
      * @property ghostMode