Force use of rustfmt.toml

Author: benalleng

treefmt.nix

@@ -20,6 +20,10 @@
   };
   settings = {
     formatter = {
+      rustfmt.options = [
+        "--config-path"
+        "./rustfmt.toml"
+      ];
       shellcheck.includes = [ "*.sh" ];
       shellcheck.excludes = [ "*.envrc" ];
       shfmt = {