fix(server-renderer): avoid using s regex flag

[sxzz]

The s (dotAll) regexp flag is not supported in ES2015.

See also https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/dotAll

The code is converted by Babel

[github-actions]

Size Report

Bundles

File	Size	Gzip	Brotli
runtime-dom.global.prod.js	91 kB	34.6 kB	31.2 kB
vue.global.prod.js	148 kB	53.8 kB	48.1 kB

Usages

Name	Size	Gzip	Brotli
createApp	51 kB	19.9 kB	18.2 kB
createSSRApp	54.3 kB	21.3 kB	19.4 kB
defineCustomElement	53.2 kB	20.7 kB	18.9 kB
overall	64.7 kB	25 kB	22.6 kB

[yyx990803]

This is server-side code so we are not limited to ES2015 but more like what is supported in latest Node LTS. dotAll seems to have been supported in Node since version 8 so I don't think this is necessary?

[sxzz]

In TypeScript 5.5, an error will occur because the target in tsconfig.json is set to ES2016.

[sxzz]

Without dotAll, the performance will be barely better

Additionally, our documentation also seems to lack the environmental requirements for the server-renderer.