Update nixpkgs.toml

Author: mattalxndr

test/examples/nixpkgs.toml

@@ -1,4 +1,4 @@
-# One CLI to format the code tree - https://git.numtide.com/numtide/treefmt
+# One CLI to format the code tree - https://github.com/numtide/treefmt
 
 [formatter.deadnix]
 command = "deadnix"
@@ -9,4 +9,4 @@ priority = 1
 [formatter.nixpkgs-fmt]
 command = "nixpkgs-fmt"
 includes = ["*.nix"]
-priority = 2
+priority = 2