Add CI check to verify MkDocs menu items (#3367)

.github/workflows/build.yml

@@ -240,3 +240,19 @@ jobs:
         ./tools/travis/run-luacheck-${{ matrix.os }}.sh
       shell: bash
 
+
+
+  doc_check:
+
+    strategy:
+      fail-fast: false
+    runs-on: ubuntu-16.04 
+      
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        submodules: false
+    - name: all_modules_linked
+      run: ./tools/check_docs_module_linkage.sh
+      shell: bash
+

tools/check_docs_module_linkage.sh

@@ -0,0 +1,10 @@
+#!/bin/bash
+
+# get all linked module docs for mkdocs.yml
+grep "modules/" mkdocs.yml | sed "s/ *- .*: *'//" | sed "s/'//" | sort > /tmp/doc
+
+# get all module and lua_module *.md files
+find docs/modules/ docs/lua-modules/ -name "*.md" | sed "sxdocs/xx" | sort > /tmp/files
+
+diff /tmp/doc /tmp/files && echo "all *.md files are reflected in mkdocs.yml"
+