doc: remove dead wiki link from readme

river is now in nixpkgs so this page and the link are undeeded.

 README.md | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/README.md b/README.md
index 8599441..6d8c6fd 100644
--- a/README.md
+++ b/README.md
@@ -44,9 +44,6 @@ installed:
 - pkg-config
 - scdoc (optional, but required for man page generation)
 
-*Note: NixOS users may refer to the
-[Building on NixOS wiki page](https://github.com/ifreund/river/wiki/Building-on-NixOS)*
-
 Then run, for example:
 ```
 zig build -Drelease-safe --prefix ~/.local install