Add a check to find broken links in docs

.github/workflows/link-check.yml

@@ -0,0 +1,29 @@
+name: Check broken links in docs
+
+on:
+  pull_request:
+    branches:
+      - master
+
+jobs:
+  check-broken-links-in-docs:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Restore lychee cache
+        uses: actions/cache@v3
+        with:
+            path: .lycheecache
+            key: cache-lychee-${{ github.sha }}
+            restore-keys: cache-lychee-
+      - name: Check links in docs/*.md
+        uses: lycheeverse/[email protected]
+        with:
+          fail: true
+          args: --base docs --accept '200,201,202,203,204,429,500' --no-progress --cache --max-cache-age 1d './docs/**/*.md' -- https://users.cecs.anu.edu.au/~steveb/pubs/papers/**
+      - name: Save lychee cache
+        uses: actions/cache/save@v3
+        if: always()
+        with:
+            path: .lycheecache
+            key: ${{ steps.restore-cache.outputs.cache-primary-key }}

.github/workflows/merge-check.yml

@@ -20,7 +20,7 @@ jobs:
           # - this action
           # - minimal tests for stable Rust (we allow them to fail)
           # - binding tests (it may take long to run)
-          ignoreActions: "ready-to-merge,check-public-api-changes,minimal-tests-core/x86_64-unknown-linux-gnu/stable,minimal-tests-core/i686-unknown-linux-gnu/stable,minimal-tests-core/x86_64-apple-darwin/stable,v8-binding-test,openjdk-binding-test,jikesrvm-binding-test,julia-binding-test,ruby-binding-test (release),ruby-binding-test (debug)"
+          ignoreActions: "ready-to-merge,check-broken-links-in-docs,check-public-api-changes,minimal-tests-core/x86_64-unknown-linux-gnu/stable,minimal-tests-core/i686-unknown-linux-gnu/stable,minimal-tests-core/x86_64-apple-darwin/stable,v8-binding-test,openjdk-binding-test,jikesrvm-binding-test,julia-binding-test,ruby-binding-test (release),ruby-binding-test (debug)"
           # This action uses API. We have a quota of 1000 per hour.
           checkInterval: 600
         env: