rustdoc query cycle regression

          I believe this caused a regression on nightly. See https://github.com/aya-rs/aya/actions/runs/15223453504/job/42822502727.

 Documenting aya-log-ebpf v0.1.1 (/home/runner/work/aya/aya/ebpf/aya-log-ebpf)
error[E0391]: cycle detected when computing revealed normalized predicates of `aya_ebpf::EbpfContext::command::{constant#0}`
  --> /home/runner/work/aya/aya/ebpf/aya-ebpf/src/lib.rs:42:38
   |
42 |     fn command(&self) -> Result<[u8; TASK_COMM_LEN], c_long> {
   |                                      ^^^^^^^^^^^^^
   |
note: ...which requires computing normalized predicates of `aya_ebpf::EbpfContext::command::{constant#0}`...
  --> /home/runner/work/aya/aya/ebpf/aya-ebpf/src/lib.rs:42:38
   |
42 |     fn command(&self) -> Result<[u8; TASK_COMM_LEN], c_long> {
   |                                      ^^^^^^^^^^^^^
   = note: ...which again requires computing revealed normalized predicates of `aya_ebpf::EbpfContext::command::{constant#0}`, completing the cycle
   = note: cycle used when normalizing `aya_ebpf::::EbpfContext::command::{constant#0}`
   = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information

For more information about this error, try `rustc --explain E0391`.
error: could not document `aya-log-ebpf`

Oddly, this seems specific to rustdoc.

Originally posted by @tamird in https://github.com/rust-lang/rust/issues/139635#issuecomment-2906771024

Reproduce the nightly rustdoc failure by documenting aya-log-ebpf and inspect ebpf/aya-ebpf/src/lib.rs:42, especially EbpfContext::command and its TASK_COMM_LEN return type. Compare rustdoc behavior with normal compilation, then use the referenced Rust compiler query documentation to trace the reported cycle. Done means identifying and resolving the rustdoc-only regression with a regression test.