Ensure no_std builds are properly documented

Author: tnull

.github/workflows/build.yml

@@ -32,7 +32,9 @@ jobs:
       - name: Cargo check
         run: cargo check --release
       - name: Check documentation
-        run: cargo doc --release
+        run: |
+          cargo doc --release
+          cargo doc --no-default-features --features no-std
       - name: Build on Rust ${{ matrix.toolchain }}
         run: cargo build --verbose --color always
       - name: Check formatting