docs(all): standardizes and adds return types, also some param fixes

src/plugins/deviceaccounts.ts

@@ -12,24 +12,28 @@ export class DeviceAccounts {
 
   /**
    *  Gets all accounts registered on the Android Device
+   * @returns {Promise<any>}
    */
   @Cordova()
   static get(): Promise<any> { return; }
 
   /**
    *  Get all accounts registered on Android device for requested type
+   * @returns {Promise<any>}
    */
   @Cordova()
   static getByType(type: string): Promise<any> { return; }
 
   /**
    *  Get all emails registered on Android device (accounts with 'com.google' type)
+   * @returns {Promise<any>}
    */
   @Cordova()
   static getEmails(): Promise<any> { return; }
 
   /**
    *  Get the first email registered on Android device
+   * @returns {Promise<any>}
    */
   @Cordova()
   static getEmail(): Promise<any> { return; }