Run prettier on all *.md files

```
prettier '{app,source}/**/**.md' --write
```

source/_talks/using-illuminate-collections-outside-laravel.md

@@ -1,22 +1,28 @@
 ---
 title: Using Illuminate Collections... Outside Laravel
-description: How to include and use Laravel’s Illuminate Collections in your non-Laravel PHP projects.
+description:
+  How to include and use Laravel’s Illuminate Collections in your non-Laravel
+  PHP projects.
 speakerdeck:
-    id: 76f1718a75a74940b0b028aac8b9f78b
-    ratio: '1.77777777777778'
-    url: https://speakerdeck.com/opdavies/using-laravel-collections-dot-dot-dot-outside-laravel-php-south-wales-august-2018
+  id: 76f1718a75a74940b0b028aac8b9f78b
+  ratio: '1.77777777777778'
+  url: https://speakerdeck.com/opdavies/using-laravel-collections-dot-dot-dot-outside-laravel-php-south-wales-august-2018
 video:
-    type: youtube
-    id: 1l0kO-iaN_o
+  type: youtube
+  id: 1l0kO-iaN_o
 tags: [nomad-php, lightning-talk, laravel, collections]
 type: Lightning talk
 events:
-    - event: nomad_php
-      date: 2017-12-21
-      time: 19:00 CET
-    - event: php_south_wales
-      date: 2018-08-28
+  - event: nomad_php
+    date: 2017-12-21
+    time: 19:00 CET
+  - event: php_south_wales
+    date: 2018-08-28
 ---
-Laravel's Illuminate Collections are a powerful object-orientated way of interacting with PHP arrays, but did you know that they can be used outside of Laravel, in any PHP project?
 
-This short talk shows how we can use Composer to include Illuminate Collections within a non-Laravel project and put them to use within your own code.
+Laravel's Illuminate Collections are a powerful object-orientated way of
+interacting with PHP arrays, but did you know that they can be used outside of
+Laravel, in any PHP project?
+
+This short talk shows how we can use Composer to include Illuminate Collections
+within a non-Laravel project and put them to use within your own code.