refactor(phpstan): Fix PHPStan reports for level 5 and 6 (#3104477)

coder_sniffer/Drupal/Sniffs/Arrays/ArraySniff.php

...fer/Drupal/Sniffs/CSS/ClassDefinitionNameSpacingSniff.php

coder_sniffer/Drupal/Sniffs/CSS/ColourDefinitionSniff.php

...niffer/Drupal/Sniffs/Classes/ClassCreateInstanceSniff.php

...r_sniffer/Drupal/Sniffs/Classes/ClassDeclarationSniff.php

coder_sniffer/Drupal/Sniffs/Classes/ClassFileNameSniff.php

...er/Drupal/Sniffs/Classes/FullyQualifiedNamespaceSniff.php

coder_sniffer/Drupal/Sniffs/Classes/InterfaceNameSniff.php

...sniffer/Drupal/Sniffs/Classes/UnusedUseStatementSniff.php

...niffer/Drupal/Sniffs/Classes/UseLeadingBackslashSniff.php

coder_sniffer/Drupal/Sniffs/Commenting/ClassCommentSniff.php

...iffer/Drupal/Sniffs/Commenting/DataTypeNamespaceSniff.php

coder_sniffer/Drupal/Sniffs/Commenting/DeprecatedSniff.php

...fer/Drupal/Sniffs/Commenting/DocCommentAlignmentSniff.php

coder_sniffer/Drupal/Sniffs/Commenting/DocCommentSniff.php

..._sniffer/Drupal/Sniffs/Commenting/DocCommentStarSniff.php

coder_sniffer/Drupal/Sniffs/Commenting/FileCommentSniff.php

...sniffer/Drupal/Sniffs/Commenting/FunctionCommentSniff.php

...er/Drupal/Sniffs/Commenting/GenderNeutralCommentSniff.php

coder_sniffer/Drupal/Sniffs/Commenting/HookCommentSniff.php