Fix SSH instructions in VM bashrc to clarify external access only

Discord Message

Author: realami Channel: #feedback Link: https://discord.com/channels/1405685085923049482/1405686161791516873/1454733235799195885

Suggestion: VMs advertise in their .bashrc that one can ssh exe.dev, but doing that on the VM itself will trigger both a fingerprint confirmation and a failure to auth (unless the user has propagated their private key to the VM manually, or via ssh-agent forwarding). Might be clearer to say:

For support and documentation, visit https://exe.dev/ or "ssh exe.dev" from your machine.