rm obsolete note

Unfortunately, JonathanHelianthicusDoe's PR has closed. Other relevant
links:
- rust-lang/crates.io#4348
- rust-lang/crates.io#3585

Author: googlebleh

README.md

@@ -2,13 +2,6 @@
 
 A smol dark theme for [crates.io](https://crates.io/).
 
-## Important Note
-
-**NOTE:** crates.io now mangles class/id names, which unfortunately sort of
-thwarts the ability to apply a usercss. Until [my PR to the crates.io
-repo](https://github.com/rust-lang/crates.io/pull/2076) gets merged, I will try
-to keep this usercss working but I cannot give any guarantees.
-
 ## Install
 
 1. Install [Stylus](https://addons.mozilla.org/firefox/addon/styl-us/)