[llvm] [DebugInfo][RemoveDIs] Add documentation for updating code to handle debug records (PR #93562)

[David Blaikie via llvm-commits]

dwblaikie wrote:

> That patch has been deliberately left hanging until the https://github.com/llvm/llvm-project/pull/91724 has landed/is about to land, just in case any change to the approach becomes necessary before then.

Given that that patch only changes the default behavior - if someone wanted to get ahead of that default switch they'd want the documentation now rather than later. And if things change, we can update the documentation - might be worth submitting this now so it's not sort of floating out here all branch-like. But I don't feel super strongly about it.

https://github.com/llvm/llvm-project/pull/93562