Docs: document rest in array/object destructuring in each blocks

[mindrones]

Closes #2676

Also completed the substitution of the code blocks language from html to sv where applicable.

[Conduitry]

I'm really wary about having 'since version such-and-such' notices in the API docs. This will become unreadable very soon unless it's done very unobtrusively. (FWIW, there also also some other new 3.1.0 and 3.2.0 features that don't currently/yet have such notes about this.)

Even if this is done unobtrusively, I'm still concerned about it resulting in sort of an append-only-docs situation. We don't want stuff to end up in its own paragraph solely because it was added in a later version. If it makes more sense to slip it in between (or partially replace) some existing documentation, we want to be free to do that, without being being hampered by finding an unambiguous place to put the 'since x.x.x' or an icon or whatever.

[MikeMatrix]

I think generally I'd leave it out.

Although there could be a consideration made to add notes or mentions of when it was added over the last minor version, to ease finding what changed in terms of features available.
Kind of a "THIS IS NEW" flag.
Not sure if that would be the right way, since this would definitely mean having to maintain the documentation a lot more and having to remove tags that would fall away in this process.
Sounds pretty tedious.

Generally I'd still refer to that through a well maintained CHANGELOG.md

[mindrones]

I've removed all the substitutions html -> sv (I had removed the versioning stuff back in May), OK to merge?