node js api document should link to LTS release from each page

[toddself]

The API documentation for the LTS stuff is a little hidden on the site -- you have to either know the LTS doc URL or always enter it from the front door, whereas nodejs.org/api is quite easy to remember.

It would be really nice if the documentation for the "live" release had a link on that page to the relevant documentation for the LTS version (if it exists).

The postgres documentation is actually an excellent example of this:

Each page has a link to various other supported (and even non-supported!) versions which makes it very easy to hop to the correct version that you're using.

[MylesBorins]

This is a great idea! I've added the good first contribution tag

/cc @nodejs/documentation

[benjamingr]

Sounds good to me +1

Let's give new contributors a chance to write this and do this ourselves if no one steps up.

[sam-github]

/cc @nodejs/website

[chris--young]

I'll take a stab at this if that's alright. It'd probably be best to build it into doc/template.html right?