Link a modal backdrop to its open Modal

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Prerequisites

• I have searched for duplicate or closed feature requests
• I have read the contributing guidelines

Proposal

Link a modal backdrop to its opeen modal by data-attribute.

So instead of

<div class="modal fade show" id="staticBackdropLive" data-bs-backdrop="static" data-bs-keyboard="false" tabindex="-1" aria-labelledby="staticBackdropLiveLabel" aria-modal="true" role="dialog" style="display: block;">
...
</div>

<div class="modal-backdrop fade show"></div>

i would propose adding the id of the modal as a data-attribute in the backdrop:

<div class="modal fade show" id="staticBackdropLive" data-bs-backdrop="static" data-bs-keyboard="false" tabindex="-1" aria-labelledby="staticBackdropLiveLabel" aria-modal="true" role="dialog" style="display: block;">
...
</div>

<div class="modal-backdrop fade show" data-id="staticBackdropLive"></div>

Motivation and context

When working with mutliple modals on top of each other, you would be able to determine, which backdrop belongs to which modal