feat(qol): configure treefmt

shells/default.nix

···
           rage
           nh
           nvfetcher
+          treefmt
           # golangci-lint
           # golangci-lint-langserver
         ])
···
       '';
     };
     perses = pkgs.mkShellNoCC {
-      packages = [dash set.terra.percli pkgs.go pkgs.gopls];
+      packages = [
+        dash
+        set.terra.percli
+        pkgs.go
+        pkgs.gopls
+      ];
     };
   }
 ) allPkgsSets

treefmt.toml

···
-# One CLI to format the code tree - https://github.com/numtide/treefmt
-
 [formatter.nix]
-# Formatter to run
 command = "nixfmt"
-# Command-line arguments for the command
-options = []
-# Glob pattern of files to include
-includes = [ "*.nix" ]
-# Glob patterns of files to exclude
-excludes = []
+includes = ["*.nix"]
+excludes = ["_sources/generated.nix"]