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/utils/obsidian.nix

@@ -12,7 +12,7 @@
         subdir = "templates";
         dateFormat = "%Y-%m-%d";
         timeFormat = "%H:%M";
-        substitutions = {};
+        substitutions = { };
       };
 
       dailyNotes = {