Issue #2314887 by Crell: Standardize shortcut entity route names.

core/modules/shortcut/shortcut.links.action.yml

core/modules/shortcut/shortcut.links.task.yml

core/modules/shortcut/shortcut.module

core/modules/shortcut/shortcut.routing.yml

core/modules/shortcut/src/Entity/Shortcut.php

core/modules/shortcut/src/Entity/ShortcutSet.php

core/modules/shortcut/src/Form/ShortcutDeleteForm.php

core/modules/shortcut/src/Form/SwitchShortcutSet.php

core/modules/shortcut/src/ShortcutForm.php