check man page update

.github/workflows/release_check.yml

@@ -1,4 +1,4 @@
-name: check_manual
+name: release_checks
 
 on:
   push:
@@ -26,6 +26,39 @@ jobs:
       - name: Compare manuals
         run: |
           if ! cmp -s doc/zstd_manual.html doc/zstd_manual_saved.html; then
-            echo "The manual was not updated before release !"
+            echo "The API manual was not updated before release !"
             exit 1
           fi
+
+  verify-man-pages:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@v3
+
+      - name: Install dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y ruby ruby-dev
+          sudo gem install ronn
+
+      - name: Display ronn version
+        run: ronn --version
+
+      - name: Save current man pages
+        run: |
+          mv programs/zstd.1 programs/zstd.1.saved
+          mv programs/zstdgrep.1 programs/zstdgrep.1.saved
+          mv programs/zstdless.1 programs/zstdless.1.saved
+
+      - name: Generate new manual pages
+        run: make -C programs man
+
+      - name: Compare man pages
+        run: |
+          for file in zstd.1 zstdgrep.1 zstdless.1; do
+            if ! cmp -s programs/$file programs/$file.saved; then
+              echo "The man page $file should have been updated."
+              exit 1
+            fi
+          done