fix(use_debug): don't get confused by nested Debug impls

[ada4a]

Fixes #15942

changelog: [use_debug]: don't get confused by nested Debug impls

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[ada4a]

@rustbot ready

[Jarcho]

A better alternative is to use an Option<OwnerId> to track this. It makes the post check just:

if self.id == Some(item.owner_id) {
  self.id = None;
}

This reduces the amount of work done here by a fair bit and leaves no room for messing up the condition if things get more complicated later.

[ada4a]

@Jarcho I must confess that I sometimes find it hard to understand your proposals as they're often very succinct -- I'd appreciate it if you could give a bit more detail. Thanks in advance:)

I think this should be what you meant