Prettified code blocks & added language extensions

Author: PawFV

docs/guide/installation/theme.md

@@ -8,30 +8,30 @@ The easiest way to create your own theme is to create a copy from one of our off
 
 If you have already setup VSF and you just want to install the theme, then you can use [vsf-cli](https://www.npmjs.com/package/%40vue-storefront/cli). First install vsf-cli:
 
-```
+```sh
 // You have to us 0.2.1 version of VSF CLI for VSF1
-npm i -g @vue-storefront/cli@0.2.1
+$ npm i -g @vue-storefront/cli@0.2.1
 // or via yarn
-yarn global add @vue-storefront/cli@0.2.1
+$ yarn global add @vue-storefront/cli@0.2.1
 ```
 
 Then run command in your project directory:
-```
-vsf init:theme
+```sh
+$ vsf init:theme
 ```
 
 Select theme:
-```
-? Select theme for Vue Storefront (Use arrow keys)
-❯ Capybara - based on Storefront UI 
-  Default 
+```sh
+$ ? Select theme for Vue Storefront (Use arrow keys)
+$ ❯ Capybara - based on Storefront UI 
+    Default 
 ```
 
 Select theme version:
-```
-? Select theme version (Use arrow keys)
-❯ Stable version (recommended for production) 
-  In development branch (could be unstable!) 
+```sh
+$ ? Select theme version (Use arrow keys)
+$ ❯ Stable version (recommended for production) 
+    In development branch (could be unstable!) 
 ```
 
 After that you should have theme in `src/themes/{themeName}`. Now what you need to do is [Create your theme](#create-your-theme).
@@ -44,7 +44,7 @@ Each theme has its own Readme file on github repository. What you need to do is
 
 After official theme installation, you need to copy it and place it in `src/themes/{themeName}`. Then you need to change its name in its `package.json` file, change the active theme in `config/local.json`:
 
-```
+```json
   "theme": "@vue-storefront/theme-myThemeName",
 ```