ci: check docs with enabled sys_rng feature (#789)

Author: newpavlov

.github/workflows/workspace.yml

@@ -102,20 +102,20 @@ jobs:
       - name: fmt
         run: cargo fmt --all -- --check
 
-  check-doc:
+  doc:
     name: rustdoc
     runs-on: ubuntu-24.04
     steps:
       - uses: actions/checkout@v6
       - uses: dtolnay/rust-toolchain@master
         with:
-          # We need Nightly for doc_auto_cfg
-          toolchain: nightly-2025-09-28
+          # We need Nightly for doc_cfg
+          toolchain: nightly-2026-01-25
       - uses: Swatinem/rust-cache@v2
       - name: Generate Docs
         env:
           RUSTDOCFLAGS: "-Dwarnings --cfg docsrs"
-        run: cargo doc --no-deps --features std
+        run: cargo doc --no-deps --features std,sys_rng
 
   typos:
     runs-on: ubuntu-latest

src/sys_rng.rs

@@ -29,6 +29,7 @@ use rand_core::{TryCryptoRng, TryRng};
 /// [rand]: https://crates.io/crates/rand
 /// [`rand::rngs::SysRng`]: https://docs.rs/rand/latest/rand/rngs/struct.SysRng.html
 /// [`Rng`]: rand_core::Rng
+/// [`UnwrapErr`]: rand_core::UnwrapErr
 #[derive(Clone, Copy, Debug, Default)]
 pub struct SysRng;