Check docs in CI

.github/workflows/ci.yml

@@ -86,6 +86,27 @@ jobs:
                    --all-features \
                    --exclude cp-benches "
 
+  docs:
+    name: Check Documentation
+    runs-on: ubuntu-latest
+    steps:
+
+    - name: Checkout
+      uses: actions/checkout@v1
+    - name: Install Rust
+      uses: actions-rs/toolchain@v1
+      with:
+        profile: minimal
+        toolchain: stable
+        override: true
+        components: rustfmt
+
+    - name: cargo doc --all --no-deps --document-private-items --all-features
+      uses: actions-rs/cargo@v1
+      with:
+        command: doc
+        args: --all --no-deps --document-private-items --all-features
+
   check_no_std:
     name: Check no_std
     runs-on: ubuntu-latest