An Editor Command for the PowerShell extension for VSCode that leverages https://gist.github.com/tylerl0706/3d1618572f7a424dab812e9cce5e3a15

registercommand.ps1

using namespace Microsoft.PowerShell.EditorServices.Protocol.MessageProtocol
using namespace Microsoft.PowerShell.EditorServices.Protocol.Messages

function Read-InputPrompt {
    param([string]$Prompt)
    end {
        $result = $psEditor.
            Components.
            Get([IMessageSender]).SendRequest(
                [ShowInputPromptRequest]::Type,
                [ShowInputPromptRequest]@{
                    Name  = $Prompt
                    Label = $Prompt
                },
                $true).
            Result

        if (-not $result.PromptCanceled) {
            $result.ResponseText
        }
    }
}

Register-EditorCommand -Name PowerShell.ConvertToVSCodeSnippet -DisplayName 'Convert selected text to a VSCode snippet' -ScriptBlock {
    $Body = $psEditor.GetEditorContext().CurrentFile.GetText($psEditor.GetEditorContext().SelectedRange)
    
    if ([string]::IsNullOrWhiteSpace($Body)) {
        Write-Error -Message 'No text selected. Select some text and try again.'
        return
    }

    $Name = ''
    while ([string]::IsNullOrWhiteSpace($Name)) {
        $Name = Read-InputPrompt 'What do you want to call your snippet?'
        if ([string]::IsNullOrWhiteSpace($Name)) {
            Write-Error -Message '''Name'' is mandatory. Please specify something for ''Name'''
        } else {
            break
        }
    }

    $Prefix = Read-InputPrompt 'What would you like the prefix to be? (default is what you put for ''Name'')'
    if(!$Prefix) {
        $Prefix = $Name
    }

    $Scope = Read-InputPrompt 'What languages would you like this to apply to (comma separated)? (default is ''all languages'')'
    $Description = Read-InputPrompt 'What is the description of the snippet? (default is none)'

    $splat = @{
        Name = $Name
        Body = $Body
        Prefix = $Prefix
        Scope = $Scope -split ','
        Description = $Description
    }

    $result = path/to/ConvertTo-VSCodeSnippet.ps1 @splat

#     $page = @"

# // Place the following snippet inside of a `.code-snippets` file. For more information on snippets, please see:
# // PLACE_LINK_HERE

# $result
# "@

    # New-EditorFile -Value $page

    $htmlContentView = New-VSCodeHtmlContentView -Title "'$Name' VSCode Snippet"
    Set-VSCodeHtmlContentView -HtmlContentView $htmlContentView -HtmlBodyContent @"
<h1>VSCode Snippet Generator</h1>
<p>Place the following snippet inside of a <code>.code-snippets</code> file. (Between curly braces <code>{}</code> !)</p>
<p>For more information on snippets, please see the official docs on <a href="PLACE_LINK_HERE">VSCode snippets</a></p>
<br/>
<h2>'$Name' VSCode Snippet</h2>
<pre>
$result
</pre>
"@
    Show-VSCodeHtmlContentView $htmlContentView
}