Docs build with warnings

Run RUSTDOCFLAGS="-D warnings" cargo doc --no-deps --features all-apis to reproduce the failures. Inspect the unresolved references in src/backend/libc/process/types.rs, src/fs/fd.rs, src/io/dup.rs, src/mm/mmap.rs, src/net/send_recv/mod.rs, src/net/socket.rs, src/pipe.rs, and src/process/rlimit.rs. Done means the documentation build completes without unresolved-link warnings.

$ RUSTDOCFLAGS="-D warnings" cargo doc --no-deps --features all-apis
error: unresolved link to `crate::process::prlimit`
  --> src/backend/libc/process/types.rs:16:18
   |
16 | /// [`prlimit`]: crate::process::prlimit
   |                  ^^^^^^^^^^^^^^^^^^^^^^^ no item named `prlimit` in module `process`
   |
   = note: `-D rustdoc::broken-intra-doc-links` implied by `-D warnings`
   = help: to override `-D warnings` add `#[allow(rustdoc::broken_intra_doc_links)]`

error: unresolved link to `crate::fs::OFlags::PATH`
   --> src/fs/fd.rs:121:23
    |
121 | /// [`OFlags::PATH`]: crate::fs::OFlags::PATH
    |                       ^^^^^^^^^^^^^^^^^^^^^^^ the struct `OFlags` has no field or associated item named `PATH`

error: unresolved link to `DupFlags::CLOEXEC`
  --> src/io/dup.rs:56:42
   |
56 | /// set `O_CLOEXEC`, use [`dup3`] with [`DupFlags::CLOEXEC`] on platforms which
   |                                          ^^^^^^^^^^^^^^^^^ the struct `DupFlags` has no field or associated item named `CLOEXEC`

error: unresolved link to `mlock_with`
   --> src/mm/mmap.rs:283:11
    |
283 | /// See [`mlock_with`] to pass additional flags.
    |           ^^^^^^^^^^ no item named `mlock_with` in scope
    |
    = help: to escape `[` and `]` characters, add '\' before them like `\[` or `\]`

error: unresolved link to `RecvFlags::TRUNC`
  --> src/net/send_recv/mod.rs:34:7
   |
34 | /// [`RecvFlags::TRUNC`] flag.
   |       ^^^^^^^^^^^^^^^^ the struct `RecvFlags` has no field or associated item named `TRUNC`

error: unresolved link to `RecvFlags::TRUNC`
   --> src/net/send_recv/mod.rs:113:7
    |
113 | /// [`RecvFlags::TRUNC`] flag.
    |       ^^^^^^^^^^^^^^^^ the struct `RecvFlags` has no field or associated item named `TRUNC`

error: unresolved link to `SocketFlags::CLOEXEC`
  --> src/net/socket.rs:17:35
   |
17 | /// To pass extra flags such as [`SocketFlags::CLOEXEC`] or
   |                                   ^^^^^^^^^^^^^^^^^^^^ the struct `SocketFlags` has no field or associated item named `CLOEXEC`

error: unresolved link to `SocketFlags::NONBLOCK`
  --> src/net/socket.rs:18:7
   |
18 | /// [`SocketFlags::NONBLOCK`], use [`socket_with`].
   |       ^^^^^^^^^^^^^^^^^^^^^ the struct `SocketFlags` has no field or associated item named `NONBLOCK`

error: unresolved link to `pipe_with`
  --> src/pipe.rs:53:11
   |
53 | /// See [`pipe_with`] to pass additional flags.
   |           ^^^^^^^^^ no item named `pipe_with` in scope
   |
   = help: to escape `[` and `]` characters, add '\' before them like `\[` or `\]`

error: unresolved link to `prlimit`
 --> src/process/rlimit.rs:8:26
  |
8 | /// [`setrlimit`], and [`prlimit`].
  |                          ^^^^^^^ no item named `prlimit` in scope
  |
  = help: to escape `[` and `]` characters, add '\' before them like `\[` or `\]`

error: could not document `rustix`