**Describe the bug** Mathjax is not loaded when creating new pages. Custom mathjax config is not loaded on page edit. **To Reproduce** Try above. **Expected behavior** Mathjax should behave same on page view, page create and page edit. **Environment** ``` Gollum 5.2.3 Running on: x86_64-linux-gnu with Ruby version 2.7.0 Using: rugged 1.1.1 gollum-rugged_adapter 1.1.1 gollum-lib 5.1.3 Markdown rendering gem: kramdown Other renderering gems: none ```