Change messages from Persons to Candidates

[nus-se-script]

Currently in both the application and in the user guide, 'persons' and 'candidates' are being used interchangeably.

Would suggest sticking to one term so that new users would not be confused :D

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_{[original: nus-cs2103-AY2324S2/pe-interim#3361] [original labels: type.DocumentationBug severity.VeryLow]}

[chiralcentre]

Team's Response

Thank you for the feedback. We assigned this a response of NotInScope as we will consider doing this in future iterations of the product, but it is technically not wrong.

Duplicate status (if any):

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