Add an example of using the nested Collapse component

Prerequisites

• I have searched for duplicate or closed issues
• I have validated any HTML to avoid common problems
• I have read the contributing guidelines

Describe the issue

In the test cases for the Collapse component, there is a use case in the form of a nested component, but this option is missing from the documentation.

Reduced test cases

Test case:

it('should collapse accordion children but not nested accordion children', () => {
      return new Promise(resolve => {
        fixtureEl.innerHTML = [
          '<div id="accordion">',
          '  <div class="item">',
          '    <a id="linkTrigger" data-bs-toggle="collapse" href="#collapseOne" aria-expanded="false" aria-controls="collapseOne"></a>',
          '    <div id="collapseOne" data-bs-parent="#accordion" class="collapse" role="tabpanel">',
          '      <div id="nestedAccordion">',
          '        <div class="item">',
          '          <a id="nestedLinkTrigger" data-bs-toggle="collapse" href="#nestedCollapseOne" aria-expanded="false" aria-controls="nestedCollapseOne"></a>',
          '          <div id="nestedCollapseOne" data-bs-parent="#nestedAccordion" class="collapse" role="tabpanel"></div>',
          '        </div>',
          '      </div>',
          '    </div>',
          '  </div>',
          '  <div class="item">',
          '    <a id="linkTriggerTwo" data-bs-toggle="collapse" href="#collapseTwo" aria-expanded="false" aria-controls="collapseTwo"></a>',
          '    <div id="collapseTwo" data-bs-parent="#accordion" class="collapse show" role="tabpanel"></div>',
          '  </div>',
          '</div>'
        ].join('')

        const trigger = fixtureEl.querySelector('#linkTrigger')
        const triggerTwo = fixtureEl.querySelector('#linkTriggerTwo')
        const nestedTrigger = fixtureEl.querySelector('#nestedLinkTrigger')
        const collapseOne = fixtureEl.querySelector('#collapseOne')
        const collapseTwo = fixtureEl.querySelector('#collapseTwo')
        const nestedCollapseOne = fixtureEl.querySelector('#nestedCollapseOne')

        function handlerCollapseOne() {
          expect(collapseOne).toHaveClass('show')
          expect(collapseTwo).not.toHaveClass('show')
          expect(nestedCollapseOne).not.toHaveClass('show')

          nestedCollapseOne.addEventListener('shown.bs.collapse', handlerNestedCollapseOne)
          nestedTrigger.click()
          collapseOne.removeEventListener('shown.bs.collapse', handlerCollapseOne)
        }

        function handlerNestedCollapseOne() {
          expect(collapseOne).toHaveClass('show')
          expect(collapseTwo).not.toHaveClass('show')
          expect(nestedCollapseOne).toHaveClass('show')

          collapseTwo.addEventListener('shown.bs.collapse', () => {
            expect(collapseOne).not.toHaveClass('show')
            expect(collapseTwo).toHaveClass('show')
            expect(nestedCollapseOne).toHaveClass('show')
            resolve()
          })

          triggerTwo.click()
          nestedCollapseOne.removeEventListener('shown.bs.collapse', handlerNestedCollapseOne)
        }

        collapseOne.addEventListener('shown.bs.collapse', handlerCollapseOne)
        trigger.click()
      })
    })

You can add this to the documentation:

<div class="accordion" id="accordionExample">
  <div class="accordion-item">
    <h2 class="accordion-header">
      <button class="accordion-button" type="button" data-bs-toggle="collapse" data-bs-target="#collapseOne" aria-expanded="true" aria-controls="collapseOne">
        Parent Accordion Item #1
      </button>
    </h2>
    <div id="collapseOne" class="accordion-collapse collapse show" data-bs-parent="#accordionExample">

      <div class="accordion" id="accordionNestedExample">
        <div class="accordion-item">
          <h2 class="accordion-header">
            <button class="accordion-button" type="button" data-bs-toggle="collapse" data-bs-target="#collapseNestedOne" aria-expanded="true" aria-controls="collapseNestedOne">
              Nested Accordion Item #1
            </button>
          </h2>
          <div id="collapseNestedOne" class="accordion-collapse collapse show" data-bs-parent="#accordionNestedExample">
            <div class="accordion-body">
              <strong>This is the first nested item’s accordion body.</strong> It is shown by default, until the collapse plugin adds the appropriate classes that we use to style each element. These classes control the overall appearance, as well as the showing and hiding via CSS transitions. You can modify any of this with custom CSS or overriding our default variables. It’s also worth noting that just about any HTML can go within the <code>.accordion-body</code>, though the transition does limit overflow.
            </div>
          </div>
        </div>

        <div class="accordion-item">
          <h2 class="accordion-header">
            <button class="accordion-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseNestedTwo" aria-expanded="false" aria-controls="collapseNestedTwo">
              Nested Accordion Item #2
            </button>
          </h2>
          <div id="collapseNestedTwo" class="accordion-collapse collapse" data-bs-parent="#accordionNestedExample">
            <div class="accordion-body">
              <strong>This is the second nested item’s accordion body.</strong> It is hidden by default, until the collapse plugin adds the appropriate classes that we use to style each element. These classes control the overall appearance, as well as the showing and hiding via CSS transitions. You can modify any of this with custom CSS or overriding our default variables. It’s also worth noting that just about any HTML can go within the <code>.accordion-body</code>, though the transition does limit overflow.
            </div>
          </div>
        </div>

        <div class="accordion-item">
          <h2 class="accordion-header">
            <button class="accordion-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseNestedThree" aria-expanded="false" aria-controls="collapseNestedThree">
              Nested Accordion Item #3
            </button>
          </h2>
          <div id="collapseNestedThree" class="accordion-collapse collapse" data-bs-parent="#accordionNestedExample">
            <div class="accordion-body">
              <strong>This is the third nested item’s accordion body.</strong> It is hidden by default, until the collapse plugin adds the appropriate classes that we use to style each element. These classes control the overall appearance, as well as the showing and hiding via CSS transitions. You can modify any of this with custom CSS or overriding our default variables. It’s also worth noting that just about any HTML can go within the <code>.accordion-body</code>, though the transition does limit overflow.
            </div>
          </div>
        </div>
      </div>

    </div>
  </div>
  <div class="accordion-item">
    <h2 class="accordion-header">
      <button class="accordion-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseTwo" aria-expanded="false" aria-controls="collapseTwo">
        Parent Accordion Item #2
      </button>
    </h2>
    <div id="collapseTwo" class="accordion-collapse collapse" data-bs-parent="#accordionExample">
      <div class="accordion-body">
        <strong>This is the second parent item’s accordion body.</strong> It is hidden by default, until the collapse plugin adds the appropriate classes that we use to style each element. These classes control the overall appearance, as well as the showing and hiding via CSS transitions. You can modify any of this with custom CSS or overriding our default variables. It’s also worth noting that just about any HTML can go within the <code>.accordion-body</code>, though the transition does limit overflow.
      </div>
    </div>
  </div>
  <div class="accordion-item">
    <h2 class="accordion-header">
      <button class="accordion-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseThree" aria-expanded="false" aria-controls="collapseThree">
        Parent Accordion Item #3
      </button>
    </h2>
    <div id="collapseThree" class="accordion-collapse collapse" data-bs-parent="#accordionExample">
      <div class="accordion-body">
        <strong>This is the third parent item’s accordion body.</strong> It is hidden by default, until the collapse plugin adds the appropriate classes that we use to style each element. These classes control the overall appearance, as well as the showing and hiding via CSS transitions. You can modify any of this with custom CSS or overriding our default variables. It’s also worth noting that just about any HTML can go within the <code>.accordion-body</code>, though the transition does limit overflow.
      </div>
    </div>
  </div>
</div>

What operating system(s) are you seeing the problem on?

Linux

What browser(s) are you seeing the problem on?

Chrome

What version of Bootstrap are you using?

v5.3

The issue does not name a documentation file. Start by locating the Collapse component documentation and its existing accordion examples, then add the supplied nested accordion example there. Done means the documentation demonstrates nested Collapse behavior and the added markup remains valid HTML.