Fix the PHP_CodeSniffer warnings/errors shown in GitLab CI tests

Now that GitLab CI tests are enabled, the warnings/errors reported by PHP_CodeSniffer must be fixed.

FILE: ...rt_scale_formatter/src/Plugin/Field/FieldFormatter/ShortScaleFormatter.php
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FOUND 3 ERRORS AFFECTING 3 LINES
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  10 | ERROR | Missing short description in doc comment
     |       | (Drupal.Commenting.DocComment.MissingShort)
 163 | ERROR | The array declaration extends to column 123 (the limit is 120).
     |       | The array content should be split up over multiple lines
     |       | (Drupal.Arrays.Array.LongLineDeclaration)
 179 | ERROR | The array declaration extends to column 123 (the limit is 120).
     |       | The array content should be split up over multiple lines
     |       | (Drupal.Arrays.Array.LongLineDeclaration)
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FILE: ...tter/web/modules/custom/short_scale_formatter/short_scale_formatter.module
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FOUND 5 ERRORS AND 3 WARNINGS AFFECTING 3 LINES
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 14 | WARNING | [ ] Hook implementations should not duplicate @param
    |         |     documentation (Drupal.Commenting.HookComment.HookParamDoc)
 14 | ERROR   | [ ] Missing parameter comment
    |         |     (Drupal.Commenting.FunctionComment.MissingParamComment)
 14 | ERROR   | [ ] Missing parameter type
    |         |     (Drupal.Commenting.FunctionComment.MissingParamType)
 15 | WARNING | [ ] Hook implementations should not duplicate @param
    |         |     documentation (Drupal.Commenting.HookComment.HookParamDoc)
 15 | ERROR   | [ ] Missing parameter comment
    |         |     (Drupal.Commenting.FunctionComment.MissingParamComment)
 16 | WARNING | [ ] Hook implementations should not duplicate @return
    |         |     documentation (Drupal.Commenting.HookComment.HookReturnDoc)
 16 | ERROR   | [x] Separate the @param and @return sections by a blank line.
    |         |     (Drupal.Commenting.DocComment.TagGroupSpacing)
 16 | ERROR   | [ ] Description for the @return value is missing
    |         |     (Drupal.Commenting.FunctionComment.MissingReturnComment)
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PHPCBF CAN FIX THE 1 MARKED SNIFF VIOLATIONS AUTOMATICALLY
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Time: 163ms; Memory: 6MB