build(aio): move doc-gen stuff from angular.io (#14097)

tools/docs/angular.io-package/processors/extractTitleFromGuides.js

@@ -0,0 +1,24 @@
+var _ = require('lodash');
+
+module.exports = function extractTitleFromGuides() {
+
+  return {
+    $runAfter: ['processing-docs'],
+    $runBefore: ['docs-processed'],
+    $process: function(docs) {
+      _(docs).forEach(function(doc) {
+        if (doc.docType === 'guide') {
+          doc.name = doc.name || getNameFromHeading(doc.description);
+        }
+      });
+    }
+  };
+};
+
+
+function getNameFromHeading(text) {
+  var match = /^\s*#\s*(.*)/.exec(text);
+  if (match) {
+    return match[1];
+  }
+}