fix(docs): typo in Intro to app-ext dev guide

docs/src/pages/app-extensions/development-guide/introduction.md

@@ -8,7 +8,7 @@ This section of the docs deals with creating your own App Extensions.
 It is assumed you have already installed one of the official App Extensions. Having this experience at your disposal is going to be very valuable when you start building your own App Extensions. If you run into problems, please visit our Discord server's channel `#app-extensions`.
 
 ## Getting started
-An App Extension is an npm package. There are two offcial kits for creating App Extensions. The official `App Extension` starter kit should be used to create App Extensions that do not provide a UI, like a component or directive, unless the objective is to install a 3rd-party library into Vue. The second official kit is the `UI` kit. This has a `ui` folder for creating your component/directive, a `ui/dev` Quasar application for testing your component/directive in isolation, and an `app-extension` folder for creating the App Extension that will be used for injecting your component/directive via the Quasar CLI into a Quasar app. The UI kit can also be used such that your component/directive can also be used with Vue CLI or UMD.
+An App Extension is an npm package. There are two official kits for creating App Extensions. The official `App Extension` starter kit should be used to create App Extensions that do not provide a UI, like a component or directive, unless the objective is to install a 3rd-party library into Vue. The second official kit is the `UI` kit. This has a `ui` folder for creating your component/directive, a `ui/dev` Quasar application for testing your component/directive in isolation, and an `app-extension` folder for creating the App Extension that will be used for injecting your component/directive via the Quasar CLI into a Quasar app. The UI kit can also be used such that your component/directive can also be used with Vue CLI or UMD.
 
 ```bash
 $ quasar create my-ext --kit app-extension