chore(doc-gen/angular.io): add ids to members so they can be linked to

Closes #4206

docs/angular.io-package/rendering/toId.js

@@ -0,0 +1,8 @@
+module.exports = function() {
+  return {
+    name: 'toId',
+    process: function(str) {
+      return str.replace(/[^(a-z)(A-Z)(0-9)._-]/, '-');
+    }
+  };
+};