Add trailing slash to authority URLs

[guardrex]

Addresses #654 (comment)

Thanks @GC-brian-taylor! 🚀 ... I'll update the article next.

BTW ... I'm going to open a separate issue to deal with getting the token (and details from the token) as you showed. I like the approach that you took. I'm going to add it to the article, and I might add a commented-out section (as you showed) to the apps. I'll probably reach the new issue in a week or so, as I'm working on a big tutorial overhaul at the moment.

UPDATES (4/20) ...

• The trailing slash is now on the existing PR for V2 token guidance. I hope to get that reviewed and merged soon.
• I opened an issue to add troubleshooting guidance on getting the token for failed requests. I'll get to it as soon as I can, probably next week.