refer/link to the new SurveyJS loop and merge feature

Author: becky-gilbert

docs/overview/building-surveys.md

@@ -271,7 +271,9 @@ Instead, it's often preferrable to separate the information that changes across
 
 The following section presents some different options for programmatically defining multiple questions in a survey trial, or multiple survey trials, based on an array of values that should change across questions or trials.
 
-The example below shows how to use the `survey_function` to loop over a set of question-level variables (titles/prompts and names), and dynamically add each question to a single survey page. You could use this same approach to add questions across multiple pages within the same survey trial.
+One option is to try the new [SurveyJS loop and merge feature](https://surveyjs.io/form-library/examples/loop-and-merge/vanillajs) (available as of `survey` plugin v3.0.0). This feature allows you to create a predefined number of question loops by linking each question loop to a row in a single- or multi-select matrix. Or, you can use a dynamic matrix or dynamic panel to generate question loops in response to participants' responses (e.g. repeat a set of questions for each choice that they selected in a checkbox question).
+
+Another, more flexible option is to use JavaScript to dynamically generate your survey structure. The example below shows how to use the `survey_function` to loop over a set of question-level variables (titles/prompts and names), and dynamically add each question to a single survey page. You could use this same approach to add questions across multiple pages within the same survey trial.
 
 ```javascript
 const survey_function = (survey) => {

docs/plugins/survey.md

@@ -512,7 +512,7 @@ import '@jspsych/plugin-survey/css/survey.css'
     <a target="_blank" rel="noopener noreferrer" href="../../demos/jspsych-survey-demo4.html">Open demo in new tab</a>
 
 ??? example "Repeating survey trials with different variables"
-    The survey plugin is not well-suited for use with the jsPsych timeline variables feature, so an alternative to creating a set of repeating survey trials is to construct them in a loop.
+    The survey plugin is not well-suited for use with the jsPsych timeline variables feature, so an alternative to creating a set of repeating survey trials is to construct them in a loop. You can also check out the [SurveyJS loop and merge feature](https://surveyjs.io/form-library/examples/loop-and-merge/vanillajs).
     When adding any data to a survey trial, you should add it via the `data` parameter at the whole-trial level (not inside the question objects), even if it only relates to one question out of multiple questions/pages contained within the trial.
     === "Code"