Use null coalesce operator instead of ternary operator.

Problem/Motivation

FILE: /var/www/html/drupal9.3.0/web/modules/contrib/back_to_top/js/back_to_top.js
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FOUND 5 ERRORS AFFECTING 5 LINES
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14 | ERROR | [x] Spaces must be used to indent lines; tabs are not allowed
15 | ERROR | [x] Spaces must be used to indent lines; tabs are not allowed
16 | ERROR | [x] Spaces must be used to indent lines; tabs are not allowed
43 | ERROR | [x] Expected 1 space after FUNCTION keyword; 0 found
55 | ERROR | [x] TRUE, FALSE and NULL must be uppercase; expected "NULL" but found "null"
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FILE: /var/www/html/drupal9.3.0/web/modules/contrib/back_to_top/src/Form/BackToTopSettingsForm.php
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FOUND 13 ERRORS AFFECTING 13 LINES
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40 | ERROR | [x] Use null coalesce operator instead of ternary operator.
46 | ERROR | [x] Use null coalesce operator instead of ternary operator.
52 | ERROR | [x] Use null coalesce operator instead of ternary operator.
58 | ERROR | [x] Use null coalesce operator instead of ternary operator.
66 | ERROR | [x] Use null coalesce operator instead of ternary operator.
85 | ERROR | [x] Use null coalesce operator instead of ternary operator.
91 | ERROR | [x] Use null coalesce operator instead of ternary operator.
102 | ERROR | [x] Use null coalesce operator instead of ternary operator.
116 | ERROR | [x] Use null coalesce operator instead of ternary operator.
125 | ERROR | [x] Use null coalesce operator instead of ternary operator.
134 | ERROR | [x] Use null coalesce operator instead of ternary operator.
143 | ERROR | [x] Use null coalesce operator instead of ternary operator.
158 | ERROR | [x] Use null coalesce operator instead of ternary operator.
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Time: 92ms; Memory: 12MB