Handle ssh known hosts addition prompt

[gmlexx]

• PR Description

Show acknowledgement dialog if ssh host key is not known by any other names.

Fix #3205.

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[jesseduffield]

Thanks for raising this @gmlexx . Could you update the confirmation message so that it's clear that it's talking about an unknown SSH host? The user may not have the command log showing.

[gmlexx]

@jesseduffield it looks like prompt input doesn't have this information, it's just the line Are you sure you want to continue connecting ...