Code block editor doesn't show contents without clicking code content #1672

Describe the bug
Code block editor doesn't show contents without clicking code content

Steps To Reproduce
Steps to reproduce the behavior:

1. Go to 'Edit' -mode
2. Add code block
3. Insert contents of 'https://github.com/BookStackApp/BookStack/blob/master/.gitignore'
4. Save Page
5. Open code block again in edit mode >> no code content visible without clicking code field

Expected behavior
Code block editor should show code content when its opened.

Configuration

• Exact BookStack Version v0.27.4
• PHP Version: 7.0.33-0+deb9u3
• Hosting Method: nginx & fastcgi