Docs: add about -Xdebug to disable "was optimise out"

[PetrakovichVictoria]

KT-54548 [Docs] Coroutine debugger: disable "was optimised out" compiler feature

[dkhalanskyjb]

I think this tip would be much better formulated if it was preceded by its context. For example, "sometimes, in the debugger, you can see optimized out next to a variable name (see the picture) [an accompanying picture]; when debugging, this is often undesired," etc. As is, it comes out of nowhere.

[PetrakovichVictoria]

@dkhalanskyjb, thanks for your previous review. Rereview, please.

[dkhalanskyjb]

Thank you, you addressed every concern neatly!

Is there a reason why this was moved to coroutines-basics.md though? I think coroutines-basics.md is a tooling-agnostic introduction, one that everyone could follow even on https://play.kotlinlang.org/. Maybe debugging.md would be a better place.

[PetrakovichVictoria]

Is there a reason why this was moved to coroutines-basics.md though?

@dkhalanskyjb, yes, because I understood that those pages where this information was before are tutorials with specific code which doesn't contain suspend fun syntax.
So, I moved this section to the first mention of suspend functions.

Maybe debugging.md would be a better place.

I agree, but this page is hidden from the TOC now, and as I know this was made consciously, I'll write you in DM.

[dkhalanskyjb]

Aside from this, I think it's good to go!