Adds cargo and adds nix to editor config.

.editorconfig

@@ -15,3 +15,7 @@ trim_trailing_whitespace = false
 
 [*.md]
 trim_trailing_whitespace = false
+
+[*.nix]
+indent_size = 2
+

flake.nix

@@ -21,6 +21,7 @@
           mkShell {
             buildInputs = [
               rustc
+              cargo
               clippy
               rustfmt
             ];