build(aio): do not try to auto-link to internal API items (#24000)

This would cause dangling links since the target, being internal,
would not exist in the docs.

PR Close #24000

aio/tools/transforms/angular-base-package/post-processors/auto-link-code.js

@@ -65,7 +65,9 @@ module.exports = function autoLinkCode(getDocFromAlias) {
     };
   }
   function foundValidDoc(docs) {
-    return docs.length === 1 && autoLinkCodeImpl.docTypes.indexOf(docs[0].docType) !== -1;
+    return docs.length === 1 &&
+           !docs[0].internal &&
+           autoLinkCodeImpl.docTypes.indexOf(docs[0].docType) !== -1;
   }
 
   function createLinkNode(doc, text) {