imp(readme): use tree-like chars for web-extension tree structure

Author: Kocal

README.md

@@ -17,37 +17,38 @@ It makes some assumptions about your project setup.
 I hope to be able to scaffold an app so that identifying the below in unnecessary.
 
 ```
-|- public/
-  |- _locales/
-    |- en/
-      |- messages.json
-  |- icons/
-    |- Icons for your extension. Should include a 16, 19, 38, 48, and 128px square image
-  |- browser-extension.html (default target html template)
-|- src/
-  |- assets/
-    |- Static assets in use in your app, like logo.png
-  |- components/
-    |- HelloWorld.vue (modified)
-  |- content-scripts
-    |- content-script.js
-  |- devtools/ (asked during project generation)
-    |- App.vue
-    |- main.js
-  |- options/ (asked during project generation)
-    |- App.vue
-    |- main.js
-  |- popup/ (asked during project generation)
-    |- App.vue
-    |- main.js
-  |- override/ (asked during project generation)
-    |- App.vue
-    |- main.js
-  |- standalone/ (asked during project generation)
-    |- App.vue
-    |- main.js
-  |- background.js
-  |- manifest.json
+.
+├── public/
+│   ├── _locales/
+│   │   └── en/
+│   │       └── messages.json
+│   ├── icons/
+│   │   └── Icons for your extension. Should include a 16, 19, 38, 48, and 128px square image
+│   └── browser-extension.html (default target html template)
+├── src/
+│   ├── assets/
+│   │   └── Static assets in use in your app, like logo.png
+│   ├── components/
+│   │   └── HelloWorld.vue (modified)
+│   ├── content-scripts
+│   │   └── content-script.js
+│   ├── devtools/ (asked during project generation)
+│   │   ├── App.vue
+│   │   └── main.js
+│   ├── options/ (asked during project generation)
+│   │   ├── App.vue
+│   │   └── main.js
+│   ├── popup/ (asked during project generation)
+│   │   ├── App.vue
+│   │   └── main.js
+│   ├── override/ (asked during project generation)
+│   │   ├── App.vue
+│   │   └── main.js
+│   └── standalone/ (asked during project generation)
+│      ├── App.vue
+│      └── main.js
+├── background.js
+└── manifest.json
 ```
 
 ## System Dependencies