Docs: Add "open example in new window" to example pages

[tordans]

On a smaller screen like a MB Air the embedded examples are really hard to use. And am never able to find the link to open them in a new window …

Feature request:

It would be great to have a button on the page that opens the example in a new window.

Example page:
https://tanstack.com/router/v1/docs/examples/react/basic?file=src%2Fmain.tsx