Update part4a.md

The current language implies that this structure change should have been already completed, not that we are going to work on it this chapter. Therefore, it is confusing to readers.

Author: joerhew

src/content/4/en/part4a.md

@@ -13,7 +13,7 @@ Let's continue our work on the backend of the notes application we started in [p
 
 Before we move into the topic of testing, we will modify the structure of our project to adhere to Node.js best practices.
 
-After making the changes to the directory structure of our project, we end up with the following structure:
+Once we make the changes to the directory structure of our project, we will end up with the following structure:
 
 ```bash
 ├── index.js