Improve debug file upload docs

[bruno-garcia]

SDK

Unity SDK

Description

Confusing on this topic has happened a few times. (here's the last) so this ticket has a suggestion to improve things:

We talk about uploading symbols on the Native Support part, but symbols are part of Unity itself, outside any native support (C# exceptions).
On the landing page: https://docs.sentry.io/platforms/unity/ we don't have any mention of debug file upload. But that's critical to get value out of Sentry.

Suggested Solution

With the Unity SDK, it's simple to get debug files uploaded since the editor does that on build.
We should point that out on the landing page. Perhaps with a screenshot (or reference the wizard flow if that covers this part too).

In addition the Native Support doc should also have a mention to that. Could be an include that is pulled on both pages.