More comprehensive error message to be used for find command

[jaejayrome]

Description: Some nitpicking here, I tried to enter a random name that doesn't exist in the addressbook but then it shows me 0 persons listed. I expected there to be a more custom error message because the output seems more for the "list" command rather than the "find" command.

Steps to Reproduce:

1. Ensure that all entries are cleared
2. use the find command on a random name

[nus-pe-bot]

Team's Response

The error message is pretty clear that there are no persons named hello in the list, which is true.

Items for the Tester to Verify

:question: Issue response

Team chose [response.Rejected]

• [ ] I disagree

Reason for disagreement: [replace this with your explanation]

---