Fix strict PHPCS errors in core/lib/Drupal/Core/Url.php

FYI for the most part, in Core, coding standards are fixed thematically rather than by file. See 🌱 [meta] Fix PHP coding standards in core Active . Changes like this which are made outside the plan are not always accepted.

Thanks for your interest in helping Drupal core meet coding standards.

As @cilefen mentioned we do not apply fixes by file, but rather by rule. We have a parent issue over at 🌱 [meta] Fix PHP coding standards in core Active with many child issues where help is needed to apply the various rules across all of Drupal core. Closing this issue as a duplicate of that.