treewide: format all files (#57)

Run `nix fmt` at the root of the repository to format all files. I've
done this on my fork and this will help me merge your changes later
without having to deal with un-formatted files.

config/plugins/editor/indent-blankline.nix

@@ -1,7 +1,7 @@
 {
   plugins = {
     indent-blankline = {
-    enable = true;
-  };
+      enable = true;
+    };
   };
 }