Sort command able to input other parameters

[nus-se-bot]

Describe the bug I am able to input other random text before the specified parameters

To Reproduce Type sort randomwordshere blah blah blah 123 !@#$%^ p/quantity d/ascending

Expected behavior Sort works, but I'm able to input random alphanumeric characters before the specified parameters

Screenshots

Additional context It would be good to update the parser to disallow any other words to be added before the specified parameters

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Reported by: @reinsheer Severity: Low

_{[original: nus-cs2103-AY1819S2/pe-dry-run#281]}

[jtankw3]

Corrected.