Add missing space before a curly

Author: fxn

guides/source/classic_to_zeitwerk_howto.md

@@ -333,7 +333,7 @@ require "rails_helper"
 
 RSpec.describe "Zeitwerk compliance" do
   it "eager loads all files without errors" do
-    expect{ Rails.application.eager_load! }.not_to raise_error
+    expect { Rails.application.eager_load! }.not_to raise_error
   end
 end
 ```