update install info

Author: silverwind

README.md

@@ -25,9 +25,8 @@
 
 ## Installation
 
-Install [Stylus](https://add0n.com/stylus.html) for either [Firefox](https://addons.mozilla.org/en-US/firefox/addon/styl-us/), [Chrome](https://chrome.google.com/webstore/detail/stylus/clngdbkpkpeebahjckkjfobafhncgmne) or [Opera](https://addons.opera.com/en-gb/extensions/details/stylus/) or [Cascadea for Safari](https://cascadea.app/) and then install using one of these methods:
-
-📦 [Install the usercss](https://raw.githubusercontent.com/StylishThemes/GitHub-Dark/master/github-dark.user.css) which supports automatic updates and customization.<br>
+1. Install [Stylus for Firefox](https://addons.mozilla.org/en-US/firefox/addon/styl-us/), [Chrome](https://chrome.google.com/webstore/detail/stylus/clngdbkpkpeebahjckkjfobafhncgmne), [Opera](https://addons.opera.com/en-gb/extensions/details/stylus/) or [Cascadea for Safari](https://cascadea.app/).
+2. Install [github-dark.user.css](https://raw.githubusercontent.com/StylishThemes/GitHub-Dark/master/github-dark.user.css).
 
 ## Additional Userstyles