oauth2: clarify redirect_uri needs to be same as auth url

[splatterxl]

This PR rewords the specification of redirect_uri at the code exchange in
the OAuth2 docs to clarify that it is shared between it and the authorization
URL.

[Lulalaby]

I would've said something like "one of your", because you can have multiple urls saved in the dev portal.

[night]

This is technically inaccurate. It is the redirect URI associated with an authorization. If the redirect URI is not specified during the authorization request, it uses the first URL registered for the application. In the token exchange, specifying the redirect URI is also optional.

[splatterxl]

I would've said something like "one of your", because you can have multiple urls saved in the dev portal.

@Lulalaby I wouldn't put this in because the discussion I referenced shows the redirect_uri has to be a specific one

This is technically inaccurate. It is the redirect URI associated with an authorization. If the redirect URI is not specified during the authorization request, it uses the first URL registered for the application. In the token exchange, specifying the redirect URI is also optional.

@night Thanks, I've updated the wording to reflect this. I didn't go into too much detail with it because part of it is stated in the Authorization URL section.