fix: add missing curly brace

Author: jmcdo29

content/fundamentals/unit-testing.md

@@ -182,6 +182,7 @@ describe('CatsController', () => {
         const mockMetadata = moduleMocker.getMetadata(token) as MockFunctionMetadata<any, any>;
         const Mock = moduleMocker.generateFromMetadata(mockMetadata);
         return new Mock();
+      }
     })
     .compile();
     controller = modRef.get(CatsController);