Use navigator.userAgent to determine the runtime

[yusukebe]

What is the feature you are proposing?

This is not a new feature. Refactoring mater. Currently, getRuntimeKey() in hono/adapter determines the runtime by checking the global object like the following:

if (typeof global?.WebSocketPair === 'function') {
  return 'workerd'
}

But, I noticed that we can use navigator.userAgent instead of it. Context: https://x.com/jasnell/status/1791106278103879835

Checking navigator.userAgent is better than global?.WebSocketPair.

[6km]

@yusukebe I'm working on a PR.

[6km]

this has been implemented and merged by #2846

[yusukebe]

Now we can close this issue. Thanks!