Improve docs.rs config, add doc CI check.

.github/workflows/ci.yml

@@ -49,3 +49,20 @@ jobs:
         with:
           components: miri
       - run: cargo miri test
+
+  doc:
+    name: cargo doc
+    # NOTE: We don't have any platform specific docs in this workspace, so we only run on Ubuntu.
+    #       If we get per-platform docs (win/macos/linux/wasm32/..) then doc jobs should match that.
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: install nightly toolchain
+        uses: dtolnay/rust-toolchain@nightly
+
+      # We test documentation using nightly to match docs.rs.
+      - name: cargo doc
+        run: cargo doc --workspace --all-features --no-deps --document-private-items
+        env:
+          RUSTDOCFLAGS: '--cfg docsrs -D warnings'

Cargo.toml

@@ -11,6 +11,12 @@ repository = "https://github.com/dfrg/swash"
 homepage = "https://github.com/dfrg/swash"
 readme = "README.md"
 
+[package.metadata.docs.rs]
+all-features = true
+# There are no platform specific docs.
+default-target = "x86_64-unknown-linux-gnu"
+targets = []
+
 [features]
 default = ["std", "scale", "render"]
 

src/lib.rs

@@ -27,6 +27,7 @@ the respective modules.
 #![allow(clippy::needless_lifetimes)]
 #![allow(clippy::redundant_static_lifetimes)]
 #![allow(clippy::too_many_arguments)]
+#![cfg_attr(docsrs, feature(doc_auto_cfg))]
 #![cfg_attr(not(any(test, feature = "std")), no_std)]
 extern crate alloc;