It is a visual studio macro that originally came from JP Boodhoo's Nothing But .NET Boot Camp class. This is it:
 Sub ConvertLine()
        If DTE.ActiveDocument Is Nothing Then Return
        Dim isOpen As Boolean = OpenUndo("ConvertLine")
        Dim selection As TextSelection = CType(DTE.ActiveDocument.Selection(), EnvDTE.TextSelection)
        selection.SelectLine()
        If selection.Text = "" Then Return
        Dim classKeyword As String = "class """
        Dim methodKeyword As String = "void """
        Dim classIndex As Integer = selection.Text.IndexOf(classKeyword)
        Dim methodIndex As Integer = selection.Text.IndexOf(methodKeyword)
        If classIndex + methodIndex < 0 Then Return
        Dim index = CType(IIf(classIndex >= 0, classIndex, methodIndex), Integer)
        Dim prefix = selection.Text.Substring(0, index) + CType(IIf(classIndex >= 0, classKeyword, methodKeyword), String)
        Dim description As String = selection.Text.Replace(prefix, String.Empty)
        Dim conversion As String = Common.ReplaceSpacesWithUnderscores(description)
        conversion = Common.ReplaceApostrophesWithUnderscores(conversion)
        conversion = Common.ReplaceQuotesWithUnderscores(conversion)
        selection.Text = prefix.Replace("""", String.Empty) + conversion
        If prefix.Contains(methodKeyword) Then selection.LineDown() Else selection.LineUp()
        selection.EndOfLine()
        CloseUndo(isOpen)
    End Sub