Add some details for non visible scrollspy elements (#36625)

* docs: add some details for non visible scrollspy elements

* Apply suggestions from code review

Co-authored-by: Julien Déramond <julien.deramond@orange.com>

* fix selectors on snippet

* Fix paragraph by a native speaker

Co-authored-by: Mark Otto <markd.otto@gmail.com>

* Update scrollspy.md

* Move from warning to own section

* Update scrollspy.md

Co-authored-by: Julien Déramond <julien.deramond@orange.com>
Co-authored-by: Julien Déramond <juderamond@gmail.com>
Co-authored-by: Mark Otto <markd.otto@gmail.com>
Co-authored-by: Mark Otto <markdotto@gmail.com>

Author: 3 people

site/content/docs/5.2/components/scrollspy.md

@@ -16,9 +16,7 @@ Scrollspy toggles the `.active` class on anchor (`<a>`) elements when the elemen
 
 - As you scroll the "spied" container, an `.active` class is added and removed from anchor links within the associated navigation. Links must have resolvable `id` targets, otherwise they're ignored. For example, a `<a href="#home">home</a>` must correspond to something in the DOM like `<div id="home"></div>`
 
-- Target elements that aren't visible will be ignored and their corresponding nav items will never receive an `.active` class.
-
-Checkout the examples below to see it in action.
+- Target elements that are not visible will be ignored. See the [Non-visible elements](#non-visible-elements) section below.
 
 ## Examples
 
@@ -330,6 +328,20 @@ Scrollspy is not limited to nav components and list groups, so it will work on a
 </div>
 ```
 
+## Non-visible elements
+
+Target elements that aren’t visible will be ignored and their corresponding nav items won't receive an `.active` class. Scrollspy instances initialized in a non-visible wrapper will ignore all target elements. Use the `refresh` method to check for observable elements once the wrapper becomes visible.
+
+```js
+document.querySelectorAll('#nav-tab>[data-bs-toggle="tab"]').forEach(el => {
+  el.addEventListener('shown.bs.tab', () => {
+    const target = el.getAttribute('data-bs-target')
+    const scrollElem = document.querySelector(`${target} [data-bs-spy="scroll"]`)
+    bootstrap.ScrollSpy.getOrCreateInstance(scrollElem).refresh()
+  })
+})
+```
+
 ## Usage
 
 ### Via data attributes