Disable Slack Wysiwyg

UPDATE (2019-12-18): The script this extension is based on no longer works (as of Slack version hash 0756f06a6f0457de4e355149a4321a9abb8befa5). For more information (or to help fix this), read the issue: https://github.com/kfahy/slack-disable-wysiwyg-bookmarklet/issues/27.

Disables Slack's new wysiwyg text editor.

Slack used to have the ability to use markdown in their text. They changed this permanently for all users without the ability to go back. Per Arthur O’Dwyer on his blog entry that was posted on Hacker News (https://quuxplusone.github.io/blog/2019/11/20/slack-rich-text-box/, 2019-11-20):

>>> Slack has just recently rolled out a “WYSIWYG text input” widget to its Web browser interface. (Apparently, the phased rollout started at the beginning of November 2019, but it’s just now starting to hit the workspaces that I participate in.) The user experience of using this new input method is really, really, really bad.

Kevin Fahy created a short script that allows users to disable the new wysiwyg editor (https://github.com/kfahy/slack-disable-wysiwyg-bookmarklet).
This extension is adapted from that script: Github: https://github.com/pocc/no-wysiwyg. To see it in action, look at the screenshot.

Inspired by the Hacker News articles: https://news.ycombinator.com/item?id=21589647, https://github.com/kfahy/slack-disable-wysiwyg-bookmarklet