Fix the issues reported by phpcs

Problem/Motivation

Getting the following errors/warnings.

FILE: /pager_for_content_type/pager_for_content_type.routing.yml
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FOUND 0 ERRORS AND 1 WARNING AFFECTING 1 LINE
-------------------------------------------------------------
 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.
-------------------------------------------------------------


FILE: /pager_for_content_type/pager_for_content_type.module
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FOUND 20 ERRORS AFFECTING 17 LINES
-------------------------------------------------------------
  50 | ERROR | [x] Short array syntax must be used to define arrays
  52 | ERROR | [x] Short array syntax must be used to define arrays
  64 | ERROR | [x] Short array syntax must be used to define arrays
  66 | ERROR | [x] Short array syntax must be used to define arrays
  86 | ERROR | [x] Short array syntax must be used to define arrays
  94 | ERROR | [x] Short array syntax must be used to define arrays
 128 | ERROR | [ ] Type hint "array" missing for $pager
 132 | ERROR | [x] Short array syntax must be used to define arrays
 155 | ERROR | [x] Short array syntax must be used to define arrays
 156 | ERROR | [x] Short array syntax must be used to define arrays
 156 | ERROR | [x] Short array syntax must be used to define arrays
 162 | ERROR | [x] Short array syntax must be used to define arrays
 163 | ERROR | [x] Short array syntax must be used to define arrays
 163 | ERROR | [x] Short array syntax must be used to define arrays
 183 | ERROR | [ ] Type hint "array" missing for $node
 184 | ERROR | [x] Short array syntax must be used to define arrays
 193 | ERROR | [x] Short array syntax must be used to define arrays
 234 | ERROR | [x] Short array syntax must be used to define arrays
 235 | ERROR | [x] Short array syntax must be used to define arrays
 235 | ERROR | [x] Short array syntax must be used to define arrays
-------------------------------------------------------------------------



FILE: /pager_for_content_type/src/Form/PagerForContentTypeSettingsForm.php
-----------------------------------------------------------------------
FOUND 9 ERRORS AND 3 WARNINGS AFFECTING 12 LINES
-----------------------------------------------------------------------
  34 | WARNING | [ ] NodeType::loadMultiple calls should be avoided in classes, use dependency injection instead
  36 | ERROR   | [x] Short array syntax must be used to define arrays
  43 | ERROR   | [x] Short array syntax must be used to define arrays
  50 | ERROR   | [x] Short array syntax must be used to define arrays
  59 | ERROR   | [x] Short array syntax must be used to define arrays
  68 | ERROR   | [x] Short array syntax must be used to define arrays
  78 | ERROR   | [x] Short array syntax must be used to define arrays
  86 | ERROR   | [x] Short array syntax must be used to define arrays
  93 | ERROR   | [x] Short array syntax must be used to define arrays
 100 | ERROR   | [x] Short array syntax must be used to define arrays
 103 | WARNING | [ ] t() calls should be avoided in classes, use \Drupal\Core\StringTranslation\StringTranslationTrait and $this->t() instead
 116 | WARNING | [ ] NodeType::loadMultiple calls should be avoided in classes, use dependency injection instead
--------------------------------------------------------------------------

Steps to reproduce

Run the following command

phpcs --standard="Drupal,DrupalPractice" --extensions=php,module,inc,install,test,profile,theme,css,info,txt,md,yml pager_for_content_type

Proposed resolution

The above errors/warnings need to be fixe