feat: make preserveComments effective in DOM renderer

[esthedebeste]

When the option preserveComments is given in a DOM render context, it'll add Comment nodes.

Also added tests.

Tests

• Run the tests with npm test and lint the project with npm run lint

[dummdidumm]

If we add this, it probably should be through enhancing the option to make it backwards compatible - e.g. an enum like "ssr" | "dom" | "both"

[Rich-Harris]

I think an enum would probably be weird, given that you're providing this option alongside generate: 'dom' | 'ssr'. We should either merge this on the basis that it's not really a breaking change (no user-observable behaviour would change, it would just enable whatever use case motivated this change in the first place), or include it in v4

[dummdidumm]

Good point regarding the enum - I'll merge this then

[Conduitry]

This has been released in 3.58.0 - thank you!