This also removes our lint for plrust_tuple_struct_self_pattern, which was made a hard error in rustc itself in 1.71.0 (as noted in various comments), so our lint is entirely redundant.
Technically we could have removed it earlier, but I forgot about this. The lint code would have needed to be changed a bunch for 1.72.0 anyway, and the fix wasn't obvious, so deleting it is better all around.
This also removes our lint for plrust_tuple_struct_self_pattern, which was made a hard error in rustc itself in 1.71.0 (as noted in various comments), so our lint is entirely redundant.
Technically we could have removed it earlier, but I forgot about this. The lint code would have needed to be changed a bunch for 1.72.0 anyway, and the fix wasn't obvious, so deleting it is better all around.