Support typo in book

[potatoqualitee]

Fixes #8485

[potatoqualitee]

Tested with this and it works 👍🏼

$config = @{
    SQLSYSADMINACCOUNTS = "ADTEST\SQL Test Admins"
    SQLUSERDBDATADIR    = "C:\MSSQL14.MSSQLSERVER\MSSQL\Data"
    SQLUSERDBLOGDIR     = "C:\MSSQL14.MSSQLSERVER\MSSQL\Data"
    SQLTEMPDBDIR        = "C:\MSSQL14.MSSQLSERVER\MSSQL\Data"
    SQLBACKUPDIR        = "C:\MSSQL14.MSSQLSERVER\MSSQL\Data"
    TCPENABLED          = "1"
    NPENABLED           = "0"
}

 $splatInstallInst = @{
    SqlInstance = "sqlcs"
    Path = "D:\"
    Version = "2019"
    Feature = "Engine"
    Configuration = $config
}
Install-DbaInstance @splatInstallInst