doc: add extra link to runtimes to make it more discoverable

[alexbozhenko]

No description provided.

[alexbozhenko]

cc @aricart

[aricart]

Isn't this duplicating what is said on the top level readme which is really the landing page for the repo?

[alexbozhenko]

@aricart
It does, but that important doc is not included anywhere in https://nats-io.github.io/nats.js/
So if someone is reading it at
https://nats-io.github.io/nats.js/core/index.html
they will find the link there.

I guess we should not assume that users will read all the docs in proper order, starting from readme.md.
They can end up there from google search, etc...
So having this extra link may reduce number of questions of the kind that I have been asking you

[aricart]

It is on the top readme!

[alexbozhenko]

@aricart
Link to runtime is present in the middle of the readme:

But it doesn't help me if I, e.g. end up at https://nats-io.github.io/nats.js/core/index.html or https://github.com/nats-io/nats.js/tree/main/core from google search

I feel like having this(a link) duplicated won't hurt, but may help, so worth adding it?