Fix formatting blockquote test
Fix formatting blockquote test

`bundle exec rspec --seed 3056` was failing; `.post .contents p` was not raising error because other post with `.contents p` was present.

Fixes #521

hepu/forem,ascendbruce/forem,hepu/forem,mauriciopasquier/forem,mauriciopasquier/forem,ascendbruce/forem