Fix the issues reported by PHP_CodeSniffer

Hello, I uploaded all the corrections, except these.
In this case, I need change ta names ta functions because is not in lowerCamel format, a example: computeCKEditor5PluginSubsetConfiguration => computeCkeditor5PluginSubsetConfiguration

FILE: .../web/modules/custom/linkit/src/Plugin/CKEditor4To5Upgrade/Linkit.php
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FOUND 3 ERRORS AFFECTING 3 LINES
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27 | ERROR | Public method name "Linkit::mapCKEditor4ToolbarButtonToCKEditor5ToolbarItem" is
| | not in lowerCamel format
34 | ERROR | Public method name "Linkit::mapCKEditor4SettingsToCKEditor5Configuration" is not
| | in lowerCamel format
59 | ERROR | Public method name "Linkit::computeCKEditor5PluginSubsetConfiguration" is not in
| | lowerCamel format
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In this case there are thow name classes into condicionals, and the issue say: Class name doesn't match filename; expected "class UpgradePathCompletenessTest".

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FOUND 1 ERROR AFFECTING 1 LINE
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14 | ERROR | Class name doesn't match filename; expected "class UpgradePathCompletenessTest"
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Help me please, I don't know what to do with these remaining issues. Thanks.

GitLab CI reports PHP_CodeSniffer errors/warnings which should be fixed.

(A merge request was not yet created. That is why I changed the status to Active.)