nyxt: change meta.platforms to platforms.all

This builds and works fine on at least aarch64 (tested on a PineBook
Pro), so I figure the arbitrary platform limitation ought to be
lifted.

pkgs/applications/networking/browsers/nyxt/default.nix

@@ -52,6 +52,6 @@ stdenv.mkDerivation rec {
     homepage = "https://nyxt.atlas.engineer";
     license = licenses.bsd3;
     maintainers = with maintainers; [ lewo ];
-    platforms = [ "x86_64-linux" ];
+    platforms = platforms.all;
   };
 }