Empty commands will display usage of `help`

[zupey]

In the User Guide, there is a note:

I'm unsure of how to trigger the help command.

For example, attempt to run this command: (add) with one blank space does not trigger the help command

[nus-se-bot]

Team's Response

That is not an empty command.

Items for the Tester to Verify

:question: Issue response

Team chose [response.Rejected]

• [ ] I disagree

Reason for disagreement: [replace this with your explanation]

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