There should be an hint to clarify that only the first SSH key could take effect for each "Public key" input

[yunmingyang]

Description of problem: For each "Public key" input, only the first SSH key takes effect, it is better to set a hint for clarifying that.

Version-Release number of selected components (if applicable): cockpit-300.1-1.el8_9.x86_64 cockpit-machines-301.1.2.gb0140b7-1.fc38.noarch libvirt-dbus-1.3.0-2.module+el8.9.0+18724+20190c23.x86_64

How reproducible: 100%

Steps to Reproduce: 1 Log in cockpit, then switch to the machines page 2 Click "Create VM", then select "Installation type" to "Cloud base image" 3 Go to the Automation tab, then click "Add SSH keys" 4 Input a SSH key without comment to the input appeared after clicking "Add SSH keys"

Actual results: 1 In step 3 and 4, there is no hint to clarify that only the first SSH key could take effect for each "Public key" input

Expected results: 1 There should be a hint to clarify that only the first SSH key could take effect for each "Public key" input

Additional info:

[jelly]

I think the solution here should be the same as we did in podman, automatically add multiple keys as new entries if multiple are provided