Under some conditions, replacing an `<img` with `![]()` can break rendering, and make the image disappear.
Context at https://meta.discourse.org/t/152801
It's very easy to forget to add `require 'rails_helper'` at the top of every core/plugin spec file, and omissions can cause some very confusing/sporadic errors.
By setting this flag in `.rspec`, we can remove the need for `require 'rails_helper'` entirely.
This allows text editors to use correct syntax coloring for the heredoc sections.
Heredoc tag names we use:
languages: SQL, JS, RUBY, LUA, HTML, CSS, SCSS, SH, HBS, XML, YAML/YML, MF, ICS
other: MD, TEXT/TXT, RAW, EMAIL
Phil Pirozhkov
Loïc Guitaut
David Taylor
Arpit Jalan
Jarek Radosz