haiku: fix readme

Author: Al Hoang

README.md

@@ -82,10 +82,10 @@ Tier 3:
   * armv7-unknown-linux-uclibceabihf
   * x86_64-fuchsia
   * x86_64-unknown-dragonfly
+  * x86_64-unknown-haiku
   * x86_64-unknown-linux-gnux32
   * x86_64-unknown-openbsd
   * x86_64-unknown-redox
-  * x86_64-unknown-haiku
 
 ## Minimum Supported Rust Version (MSRV)