Update warnings when deleting route questions

[SamJamCul]

What problem does this pull request solve?

https://trello.com/c/NL0r23hr/3142-update-warnings-when-deleting-a-question-at-the-start-or-end-of-a-route-if-multiple-branches-is-enabled

The warning notification when deleting a page will reflect the routing situation around the page - if there are one or more routes to or from the page, the banner will describe this accordingly.

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[github-actions]

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[hannahkc]

Content looks grand and all the right messages show for the right situations. yay thanks!