Review Coding standard modules

Hi @rsych
I've tested the module, so it does a great job!
I like the way you followed the coding but there is still some minor stuff to adjust:

$ phpcs --standard=Drupal --extensions=php,module,inc,install,test,profile,theme,css,info,txt,md,yml web/modules/contrib/simple_percentage_field

FILE: C:\Ampps\www\my_coding_review\web\modules\contrib\simple_percentage_field\README.md
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FOUND 0 ERRORS AND 1 WARNING AFFECTING 1 LINE
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 27 | WARNING | Line exceeds 80 characters; contains 97 characters
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FILE: C:\Ampps\www\my_coding_review\web\modules\contrib\simple_percentage_field\simple_percentage_field.info.yml
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FOUND 0 ERRORS AND 3 WARNINGS AFFECTING 1 LINE
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 1 | WARNING | Remove "project" from the info file, it will be added by drupal.org packaging automatically
 1 | WARNING | Remove "datestamp" from the info file, it will be added by drupal.org packaging automatically
 1 | WARNING | Remove "version" from the info file, it will be added by drupal.org packaging automatically
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FILE: C:\Ampps\www\my_coding_review\web\modules\contrib\simple_percentage_field\src\Plugin\Field\FieldFormatter\SimplePercentageDefaultFormatter.php
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FOUND 6 ERRORS AFFECTING 6 LINES
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 34 | ERROR | [x] Array indentation error, expected 6 spaces but found 8
 35 | ERROR | [x] Array indentation error, expected 6 spaces but found 8
 36 | ERROR | [x] Array indentation error, expected 6 spaces but found 8
 37 | ERROR | [x] Array indentation error, expected 6 spaces but found 8
 38 | ERROR | [x] Array indentation error, expected 6 spaces but found 8
 39 | ERROR | [x] Array closing indentation error, expected 4 spaces but found 6
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PHPCBF CAN FIX THE 6 MARKED SNIFF VIOLATIONS AUTOMATICALLY
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FILE: C:\Ampps\www\my_coding_review\web\modules\contrib\simple_percentage_field\src\Plugin\Field\FieldType\SimplePercentageItem.php
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FOUND 3 ERRORS AFFECTING 3 LINES
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 71 | ERROR | [x] Array indentation error, expected 6 spaces but found 8
 72 | ERROR | [x] Array indentation error, expected 6 spaces but found 8
 73 | ERROR | [x] Array closing indentation error, expected 4 spaces but found 6
-----------------------------------------------------------------------------------------------------------------------------------
PHPCBF CAN FIX THE 3 MARKED SNIFF VIOLATIONS AUTOMATICALLY
-----------------------------------------------------------------------------------------------------------------------------------


FILE: C:\Ampps\www\my_coding_review\web\modules\contrib\simple_percentage_field\src\Plugin\Field\FieldWidget\SimplePercentageDefaultWidget.php
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FOUND 2 ERRORS AFFECTING 1 LINE
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 46 | ERROR | [x] Separate the @param and @return sections by a blank line.
 46 | ERROR | [ ] Description for the @return value is missing
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PHPCBF CAN FIX THE 1 MARKED SNIFF VIOLATIONS AUTOMATICALLY
----------------------------------------------------------------------------------------------------------------------------------------------

Time: 189ms; Memory: 10MB

$ phpcs --standard=DrupalPractice --extensions=php,module,inc,install,test,profile,theme,css,info,txt,md,yml web/modules/contrib/simple_percentage_field

FILE: C:\Ampps\www\my_coding_review\web\modules\contrib\simple_percentage_field\src\Plugin\Field\FieldType\SimplePercentageItem.php
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FOUND 0 ERRORS AND 2 WARNINGS AFFECTING 2 LINES
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 84 | WARNING | t() calls should be avoided in classes, use \Drupal\Core\StringTranslation\StringTranslationTrait and $this->t() instead
 91 | WARNING | t() calls should be avoided in classes, use \Drupal\Core\StringTranslation\StringTranslationTrait and $this->t() instead
-----------------------------------------------------------------------------------------------------------------------------------------

Time: 435ms; Memory: 8MB

Thanks!