Fix Coding Standard

FILE: \scroll_top_button\js\scroll.top.button.js
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FOUND 9 ERRORS AFFECTING 9 LINES
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  5 | ERROR | [x] Whitespace found at end of line
 12 | ERROR | [x] Functions must not contain multiple empty lines in a row; found 2 empty lines
 13 | ERROR | [x] Whitespace found at end of line
 16 | ERROR | [x] Whitespace found at end of line
 25 | ERROR | [x] Whitespace found at end of line
 39 | ERROR | [x] Whitespace found at end of line
 66 | ERROR | [x] Whitespace found at end of line
 69 | ERROR | [x] Whitespace found at end of line
 70 | ERROR | [x] Expected 1 newline at end of file; 0 found
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