Docs: Add bun to CLI installation scripts

[deadcoder0904]

For example, https://docs.polar.sh/integrate/sdk/adapters/tanstack-start has pnpm install

Would love bun and other alternatives like npm, yarn, pnpm, bun, deno added to the docs for easy copy-paste.

See how Deno's JSR has it: https://jsr.io/@coven/cron

I personally like Next.js one: https://nextjs.org/docs/app/getting-started/installation