feat(useScroll): support setting scroll position and toggling smooth scrolling

[curtgrimes]

Description

feat(useScroll): support setting scroll position and toggling smooth scrolling

Add ability to set scroll values and turn on or off smooth scrolling.

fix #1978

Demo

use-scroll-2.mov

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

Before submitting the PR, please make sure you do the following

• Read the Contributing Guidelines.
• Read the Pull Request Guidelines.
• Check that there isn't already a PR that solves the problem the same way to avoid creating a duplicate.
• Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).
• Ideally, include relevant tests that fail without this PR but pass with it.

[wheatjs]

LGTM

[curtgrimes]

I added f38444e to fix this issue when scrolling the demo. (This was happening before the other changes introduced in this PR if you changed the zoom level of the webpage.) no longer relevant, see #1996 (comment)

[wheatjs]

@curtgrimes maybe it would be better to implement this into useScroll as we might want to deprecate useWindowScroll in favor of useScroll

[curtgrimes]

@wheatjs Ok, should useWindowScroll() be formally deprecated if we don't want to add new features to it? Is there documentation written somewhere where I can see which composables are being considered for deprecation so I do not look at improving those?

I can look at moving this functionality into useScroll() instead if useWindowScroll() should be formally deprecated.

[wheatjs]

@wheatjs Ok, should useWindowScroll() be formally deprecated if we don't want to add new features to it? Is there documentation written somewhere where I can see which composables are being considered for deprecation so I do not look at improving those?

I can look at moving this functionality into useScroll() instead if useWindowScroll() should be formally deprecated.

Anthony and I briefly discussed it a couple days ago. Most functions are unlikely to be deprecated, we are only thinking about this one since it duplicates functionality

[curtgrimes]

Thanks. I'll migrate these changes over to useScroll.

[curtgrimes]

I have moved this functionality from useWindowScroll to useScroll.

[curtgrimes]

Resolved merge conflict.

[curtgrimes]

@antfu @wheatjs Please let me know if there's anything you need from me to push this forward. Thanks!