Description

This PR builds on the current Java code snippets to add missing code snippets to the external Classroom API documentation.

Fixes # (issue)

I added the following classes:

• ListStudentSubmissions
• ListSubmissions
• ModifyAttachmentsStudentSubmission
• PatchStudentSubmission
• ReturnStudentSubmission

Is it been tested?

• [x ] Development testing done

Checklist

• [x ] My code follows the style guidelines of this project
• [x ] I have performed a self-review of my own code
• [x ] I have performed a peer-reviewed with team member(s)
• [x ] I have commented my code, particularly in hard-to-understand areas
• [Doc changes can be made once the code is merged. ] I have made corresponding changes to the documentation
• [x ] My changes generate no new warnings
• [N/A ] Any dependent changes have been merged and published in downstream modules