Fix phpcs and phpstan warnings [#3581803]

There are a few warnings appearing in the pipeline:

phpcs reports that the tugboat config is missing a newline at the end of the file.
phpstan (previous major) warns because the LegacyHook and Hook attributes don't exist in Drupal 10.

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Fix the missing newline, and add a phpstan baseline file to ignore the LegacyHook warnings.

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3581803-fix-phpcs-and changes, plain diff MR !29
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