Manual Vercel Installation Instructions for Hono Support

[mmurrs]

Adding Vercel manually to the base Frog template, under the Devtool section, the docs include:

if (import.meta.env?.MODE === 'development') devtools(app, { serveStatic })
else devtools(app, { assetsPath: '/.frog' })

Which the import.meta is only supported in Vite and not hono. Request for the instructions to include the proper snippet for Vercel integration in Hono.
Docs: https://frog.fm/platforms/vercel#setup-devtools

[dalechyn]

Transferred to an issue #487