Lint cargo doc in CI

Author: DanGould

.github/workflows/rust.yml

@@ -49,8 +49,10 @@ jobs:
         uses: Swatinem/rust-cache@v2
       - name: "Install clippy"
         run: rustup component add clippy --toolchain nightly-x86_64-unknown-linux-gnu
-      - name: "Run linting"
+      - name: "Run code linting"
         run: bash contrib/lint.sh
+      - name: "Run documentation linting"
+        run: RUSTDOCFLAGS="-D warnings" cargo doc --no-deps --all-features --document-private-items
 
   Coverage:
     name: Code coverage