Fix the issues reported by phpcs

Problem/Motivation

Found this issues reported by phpcs:

FILE: /Users/studenttrainees/Drupal.org/drupalorg-site/docroot/modules/contrib/pdf/pdf.module
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FOUND 11 ERRORS AND 1 WARNING AFFECTING 8 LINES
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  1 | ERROR   | [x] Missing file doc comment
  7 | ERROR   | [x] Spaces must be used to indent lines; tabs are not allowed
  7 | ERROR   | [x] Line indented incorrectly; expected 2 spaces, found 1
  8 | ERROR   | [x] Spaces must be used to indent lines; tabs are not allowed
  8 | ERROR   | [x] Array indentation error, expected 3 spaces but found 2
  9 | ERROR   | [x] Spaces must be used to indent lines; tabs are not allowed
  9 | ERROR   | [x] Array indentation error, expected 4 spaces but found 3
 10 | ERROR   | [x] Spaces must be used to indent lines; tabs are not allowed
 10 | WARNING | [x] A comma should follow the last multiline array item. Found: NULL
 11 | ERROR   | [x] Spaces must be used to indent lines; tabs are not allowed
 12 | ERROR   | [x] Spaces must be used to indent lines; tabs are not allowed
 13 | ERROR   | [x] Spaces must be used to indent lines; tabs are not allowed
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PHPCBF CAN FIX THE 12 MARKED SNIFF VIOLATIONS AUTOMATICALLY
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FILE: /Users/studenttrainees/Drupal.org/drupalorg-site/docroot/modules/contrib/pdf/css/pdf.css
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FOUND 3 ERRORS AFFECTING 3 LINES
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  1 | ERROR | [x] End of line character is invalid; expected "\n" but found "\r\n"
  2 | ERROR | [x] Expected 1 space after colon in style definition; 0 found
 33 | ERROR | [x] Blank lines are not allowed in class definitions
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PHPCBF CAN FIX THE 3 MARKED SNIFF VIOLATIONS AUTOMATICALLY
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FILE: /Users/studenttrainees/Drupal.org/drupalorg-site/docroot/modules/contrib/pdf/pdf.routing.yml
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FOUND 0 ERRORS AND 1 WARNING AFFECTING 1 LINE
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 7 | WARNING | The administration page callback should probably use "administer site
   |         | configuration" - which implies the user can change something - rather than "access
   |         | administration pages" which is about viewing but not changing configurations.
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FILE: ...studenttrainees/Drupal.org/drupalorg-site/docroot/modules/contrib/pdf/src/Form/ConfigForm.php
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FOUND 0 ERRORS AND 1 WARNING AFFECTING 1 LINE
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 10 | WARNING | The class short comment should describe what the class does and not simply repeat
    |         | the class name
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FILE: ...l.org/drupalorg-site/docroot/modules/contrib/pdf/src/Plugin/Field/FieldFormatter/PdfPages.php
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FOUND 8 ERRORS AND 3 WARNINGS AFFECTING 11 LINES
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  8 | WARNING | [x] Unused use statement
 10 | ERROR   | [ ] Missing short description in doc comment
 20 | ERROR   | [x] Missing function doc comment
 26 | ERROR   | [x] Missing function doc comment
 29 | WARNING | [ ] t() calls should be avoided in classes, use
    |         |     \Drupal\Core\StringTranslation\StringTranslationTrait and $this->t() instead
 35 | ERROR   | [x] Missing function doc comment
 42 | WARNING | [ ] t() calls should be avoided in classes, use
    |         |     \Drupal\Core\StringTranslation\StringTranslationTrait and $this->t() instead
 48 | ERROR   | [x] Missing function doc comment
 57 | ERROR   | [x] No space found before comment text; expected "// '#value' => TODO," but found
    |         |     "//'#value' => TODO,"
 82 | ERROR   | [x] Expected 1 blank line after function; 0 found
 83 | ERROR   | [x] The closing brace for the class must have an empty line before it
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PHPCBF CAN FIX THE 8 MARKED SNIFF VIOLATIONS AUTOMATICALLY
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FILE: ...g/drupalorg-site/docroot/modules/contrib/pdf/src/Plugin/Field/FieldFormatter/PdfThumbnail.php
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FOUND 9 ERRORS AND 6 WARNINGS AFFECTING 14 LINES
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   8 | WARNING | [x] Unused use statement
  10 | ERROR   | [ ] Missing short description in doc comment
  19 | ERROR   | [x] Missing function doc comment
  19 | ERROR   | [x] Expected 1 blank line before function; 0 found
  27 | ERROR   | [x] Missing function doc comment
  31 | WARNING | [ ] t() calls should be avoided in classes, use
     |         |     \Drupal\Core\StringTranslation\StringTranslationTrait and $this->t() instead
  38 | WARNING | [ ] t() calls should be avoided in classes, use
     |         |     \Drupal\Core\StringTranslation\StringTranslationTrait and $this->t() instead
  44 | WARNING | [ ] t() calls should be avoided in classes, use
     |         |     \Drupal\Core\StringTranslation\StringTranslationTrait and $this->t() instead
  49 | ERROR   | [x] Missing function doc comment
  59 | WARNING | [ ] t() calls should be avoided in classes, use
     |         |     \Drupal\Core\StringTranslation\StringTranslationTrait and $this->t() instead
  62 | WARNING | [x] A comma should follow the last multiline array item. Found: $height
  68 | ERROR   | [x] Missing function doc comment
  76 | ERROR   | [x] No space found before comment text; expected "// '#value' => ," but found
     |         |     "//'#value' => ,"
 103 | ERROR   | [x] Expected 1 blank line after function; 0 found
 104 | ERROR   | [x] The closing brace for the class must have an empty line before it
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PHPCBF CAN FIX THE 10 MARKED SNIFF VIOLATIONS AUTOMATICALLY
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FILE: ...org/drupalorg-site/docroot/modules/contrib/pdf/src/Plugin/Field/FieldFormatter/PdfDefault.php
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FOUND 1 ERROR AND 7 WARNINGS AFFECTING 4 LINES
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  10 | ERROR   | Missing short description in doc comment
  46 | WARNING | t() calls should be avoided in classes, use
     |         | \Drupal\Core\StringTranslation\StringTranslationTrait and $this->t() instead
 139 | WARNING | t() calls should be avoided in classes, use
     |         | \Drupal\Core\StringTranslation\StringTranslationTrait and $this->t() instead
 139 | WARNING | t() calls should be avoided in classes, use
     |         | \Drupal\Core\StringTranslation\StringTranslationTrait and $this->t() instead
 139 | WARNING | t() calls should be avoided in classes, use
     |         | \Drupal\Core\StringTranslation\StringTranslationTrait and $this->t() instead
 139 | WARNING | Do not concatenate strings to translatable strings, they should be part of the
     |         | t() argument and you should use placeholders
 139 | WARNING | t() calls should be avoided in classes, use
     |         | \Drupal\Core\StringTranslation\StringTranslationTrait and $this->t() instead
 153 | WARNING | \Drupal calls should be avoided in classes, use dependency injection instead
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Time: 277ms; Memory: 10MB

Steps to reproduce

Run this command in the module folder: phpcs --standard=Drupal,DrupalPractice --extensions=php,module,inc,install,test,profile,theme,css,info,txt,md,yml

Proposed resolution

Remaining tasks

FILE: ...org/drupalorg-site/docroot/modules/contrib/pdf/src/Plugin/Field/FieldFormatter/PdfDefault.php
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FOUND 0 ERRORS AND 1 WARNING AFFECTING 1 LINE
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156 | WARNING | \Drupal calls should be avoided in classes, use dependency injection instead
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Time: 214ms; Memory: 10MB