ci: really check docs for warnings (#357)

Author: Stebalien

.github/workflows/ci.yml

@@ -10,6 +10,7 @@ env:
   CARGO_TARGET_WASM32_WASIP1_RUNNER: "/home/runner/.wasmtime/bin/wasmtime --dir /tmp/"
   CARGO_TARGET_WASM32_WASIP2_RUNNER: "/home/runner/.wasmtime/bin/wasmtime --dir /tmp/"
   RUSTFLAGS: "-D warnings"
+  RUSTDOCFLAGS: "-D warnings"
 
 name: CI
 jobs:
@@ -104,5 +105,3 @@ jobs:
         run: cargo doc --all --no-deps
       - name: Check for clippy lints
         run: cargo clippy
-      - name: Check for clippy lints
-        run: cargo clippy