MDL-78316 core: Improve jsdoc typedef for icons

lib/amd/src/icon_system_fontawesome.js

@@ -28,6 +28,13 @@ import * as Mustache from './mustache';
 import * as Config from './config';
 import * as Url from './url';
 
+/**
+ * An set of properties for an icon.
+ * @typedef {object} IconProperties
+ * @property {array} attributes
+ * @private
+ */
+
 /**
  * The FontAwesome icon system.
  */
@@ -154,13 +161,13 @@ export default class IconSystemFontawesome extends IconSystem {
     }
 
     /**
-     * Get the unamapped icon content, if the icon is not mapped.
+     * Get the unmapped icon content, if the icon is not mapped.
      *
-     * @param {object<attributes<array>>} mappedIcon
+     * @param {IconProperties} mappedIcon
      * @param {string} key
      * @param {string} component
-     * @param {StaticRange} title
-     * @returns {object<attributes<array>>|null}
+     * @param {string} title
+     * @returns {IconProperties|null}
      * @private
      */
     getUnmappedIcon(mappedIcon, key, component, title) {