fix code sniffer white space errors in simple-plugin/demoPlugin/main.inc
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FOUND 3 ERRORS AFFECTING 3 LINES
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5 | ERROR | [x] Whitespace found at end of line
10 | ERROR | [x] Whitespace found at end of line
15 | ERROR | [x] Whitespace found at end of line
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PHPCBF CAN FIX THE 3 MARKED SNIFF VIOLATIONS AUTOMATICALLY
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