Update file-preface.md

adding some information about formatting of TW entries

2024-participants/interested-technical-writers/file-preface.md

@@ -20,9 +20,13 @@ To add your information to the [interested technical writers](./interested-techn
 
     `Jane Doe | [Portfolio](https://janedoe.example.com), [résumé](https://janedoe.example.com/resume) | Skilled in API documentation, writing tutorials`
 
-2. Save your Markdown file as YOURNAME.md. **Important: do not use any spaces in the filename**
+     **Important: Your entry should not include any line breaks. Do not include blank lines after your entry.**
 
-3. [Create a pull request](https://docs.github.com/en/github/collaborating-with-issues-and-pull-requests/creating-a-pull-request) to add your file to the [interested-technical-writers](./interested-technical-writers) directory.
+2. Save your Markdown file as YOURNAME.md. 
+
+    **Important: do not use any spaces in the filename**
+
+4. [Create a pull request](https://docs.github.com/en/github/collaborating-with-issues-and-pull-requests/creating-a-pull-request) to add your file to the [interested-technical-writers](./interested-technical-writers) directory.
 
 _NOTE: To add your information to this repo you will need to sign the Google CLA. For more information on the CLA, see [the Google CLA page](https://cla.developers.google.com/about)._