"az vm access set-linux-user" should load pub key from ~/.ssh if not provided

[JasonRShaver]

SSH should use the same defaulting logic as AZ VM CREATE to identify the username if an SSH key is provided.
Username should only be required is an SSH key is not provided.
Password has a bad description
Name is missing the description (name of the virtual machine)
If no username, password, or ssh key is provided, it should look to ~/.ssh as a default.

$ az vm access set-linux-user --help

Command
    az vm access set-linux-user

Arguments
    --name -n           [Required]
    --resource-group -g [Required]: Name of resource group.
    --username -u       [Required]: The user name.
    --password -p                 : The user name.
    --ssh-key-value               : SSH key file value or key file path.

Global Arguments
    --debug                       : Increase logging verbosity to show all debug logs.
    --help -h                     : Show this help message and exit.
    --output -o                   : Output format.  Allowed values: json, tsv, list.  Default: json.
    --query                       : JMESPath query string. See http://jmespath.org/ for more
                                    information and examples.
    --verbose                     : Increase logging verbosity. Use --debug for full debug logs.

[JasonRShaver]

@yugangw-msft

[yugangw-msft]

the parameter naming and help bugs were caused by recent command registration rework, which i can correct. The defaulting to '~/.ssh' , i thought about that as well, since you are also asking this, i will go ahead to do it.

[yugangw-msft]

please note, i have not got enough reason to make the username optional. We are adding a user to an existing VM which we have defaulted the name on creation, so users likely add a new user when executing this command.
Updating the issue title