Added Offcanvas scroll after close option

[Xcreen]

Description

I added a option scrollAfterClose to be able to disable the scrolling to the offcanvas toggler after the offcanvas is closed.

Motivation & Context

Currently after the offcanvas is closed, the body always scrolling back to the offcanvas toggler position.
When enable offcanvas bodyscrolling and add anchor-links into the offcanvas, the links dont work.

Type of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Refactoring (non-breaking change)
• Breaking change (fix or feature that would change existing functionality)

Checklist

• I have read the contributing guidelines
• My code follows the code style of the project (using npm run lint)
• My change introduces changes to the documentation
• I have updated the documentation accordingly
• I have added tests to cover my changes
• All new and existing tests passed

Live previews

• https://deploy-preview-40553--twbs-bootstrap.netlify.app/

Related issues

Closes #38070

[patrickhlauke]

noting that this isn't about scrolling. scrolling is a side effect of focus being (correctly) set back to the element that triggered the offcanvas. so, at the very least, rename this to be about focus, not scroll.

[Xcreen]

As suggested, I have changed the name of the option.

scrollAfterClose > focusAfterClose

[XhmikosR]

Unfortunately, this still needs tests.

[mdo]

Superseded by #42544 for v6. The underlying problem here — closing the panel scrolls the page back to the toggler, breaking anchor links inside it — is resolved in v6's Drawer by restoring focus with { preventScroll: true } (focus still returns to the trigger for accessibility, but the page no longer jumps). v6 also renamed Offcanvas to Drawer, so this patch to offcanvas.js no longer applies.

The configurable opt-out this PR adds (scrollAfterClose / focusAfterClose) was not carried over — if you still want an API to skip focus-restore entirely, please open a fresh feature request against v6-dev.

Closing.