feat(fromEvent): support HTMLElement

[rorry121]

Description

Hi, thanks to @vueuse and @vueuse/rxjs，I can use rxjs in vue easily.
The fromEvent function support Ref<HTMLElement>, and code:

import { fromEvent } from '@vueuse/rxjs'
import { fromEvent as fromEventRx } from "rxjs";
const mousedown$ = fromEvent(resizeAnchorRef!, 'mousedown');
const mouseup$ = fromEventRx(document.body, 'mouseup');
const mousemove$ = fromEventRx(document.body, 'mousemove');

Expect fromEvent can also support HTMLElement, so I can use like this:

import { fromEvent } from '@vueuse/rxjs'
const mousedown$ = fromEvent(resizeAnchorRef!, 'mousedown');
const mouseup$ = fromEvent(document.body, 'mouseup');
const mousemove$ = fromEvent(document.body, 'mousemove');

Additional context

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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.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.