internal/functions/ConvertFrom-MarkdownLine.ps1

function ConvertFrom-MarkdownLine
{
<#
    .SYNOPSIS
        Converts markdown notation of bold and cursive to html.
     
    .DESCRIPTION
        Converts markdown notation of bold and cursive to html.
     
    .PARAMETER Line
        The line of text to convert.
     
    .EXAMPLE
        PS C:\> Convert-MarkdownLine -Line '_value1_'
     
        Will convert "_value1_" to "<i>value1</i>"
#>

    [CmdletBinding()]
    param (
        [Parameter(ValueFromPipeline = $true, Mandatory = $true)]
        [string[]]
        $Line
    )
    
    process
    {
        foreach ($string in $Line) {
            $string -replace '\*\*(.+?)\*\*', '<b>$1</b>' -replace '_(.+?)_', '<i>$1</i>'
        }
    }
}