rustdoc: Don't distinguish structs and tuple structs with only private fields

[clarfonthey]

For example, AddrParseError shows up as pub struct AddrParseError(_); and Ipv4Addr shows up as pub struct Ipv4Addr { /* fields omitted */ }

I feel like all structs should show up as the latter form if all of the fields are private. It technically doesn't matter that the struct is a tuple struct if the fields are all private. It's not a huge deal but it's an inconsistency that looks off to me.

[bluss]

Yes, it is time, because the relevant part of #35626 is stable in nightly.

[steveklabnik]

Triage: this bug still reproduces

[clarfonthey]

This bug still reproduces, in case you were wondering.

[jsha]

/cc @camelid who might be interested because it's similar in nature to #92699.

[camelid]

Yeah, it's always bothered me that tuple structs with all private fields show how many fields they have, even though they're supposed to be fully private.

[clarfonthey]

Bonus points if you make it so that it has the struct-field syntax if there are a mix of private/public fields, e.g. Struct { 1: T, /* some fields hidden */ }