[PATCH] ntdll: Truncate and ellipsize debug output if it's too long.

[Esme Povirk (she/they)]

Is there anything I can do to help move this along?

append_output only interacts with one other function, and this doesn't
change the interface to it, so from a correctness perspective, I think
this should be easy to verify.

>From a design perspective, I don't know if this is right, but I
couldn't think of a better approach. Exposing the buffer size to
callers seems not ideal to me. Is there an alternative I'm missing?