Drop hide-markdown-diff feature (#4655)

readme.md

@@ -181,7 +181,6 @@ Thanks for contributing! 🦋🙌
 - [](# "file-finder-buffer") [Lets you start typing your search immediately after invoking the File Finder (<kbd>t</kbd>), instead of having you wait for it to load first.](https://user-images.githubusercontent.com/1402241/75542106-1c811700-5a5a-11ea-8aa5-bea0472c59e2.gif)
 - [](# "show-associated-branch-prs-on-fork") [Shows the associated pull requests on branches for forked repositories.](https://user-images.githubusercontent.com/16872793/81504659-7e5ec800-92b8-11ea-9ee6-924110e8cca1.png)
 - [](# "html-preview-link") [Adds a link to preview HTML files.](https://user-images.githubusercontent.com/44045911/67634792-48995980-f8fb-11e9-8b6a-7b57d5b12a2f.png)
-- [](# "hide-markdown-diff") 🔥 [When editing Markdown files, it lets you hide the Markdown diff in the preview.](https://user-images.githubusercontent.com/46634000/108093883-7f5e2a80-707e-11eb-9328-cb902a1061c7.gif)
 - [](# "collapse-wiki-sections") [Lets you collapse sections in Wikis and help you see the outline of the document.](https://user-images.githubusercontent.com/46634000/110379737-7cd86a80-8057-11eb-92e2-aed6b0fe35b2.gif)
 
 <!-- Refer to style guide above. Keep this message between sections. -->

source/refined-github.ts

@@ -202,7 +202,6 @@ import './features/rgh-feature-descriptions';
 import './features/wait-for-attachments';
 import './features/useful-forks';
 import './features/link-to-changelog-file';
-import './features/hide-markdown-diff';
 import './features/rgh-sponsor-button';
 import './features/rgh-linkify-features';
 import './features/collapse-wiki-sections';