Since this community is not limited to code editors, I wanted to share the markdown editor I use: Zettlr.
To be honest, it is not as polished as the most popular editors backed up by companies. But it is free software that pays attention to standards and integrates very well with Zotero (for those who does academic writing).
I love it. I use it to document my work.
It’s a nice balance between markdown and WYSIWYG editor.