ci: fix toolchain for docs

Author: threadexio

.github/workflows/ci.yaml

@@ -25,6 +25,8 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@nightly
+        with:
+          - toolchain: nightly
       - uses: dtolnay/install@cargo-docs-rs
-      - run: cargo docs-rs
+      - run: cargo +nightly docs-rs