`ToCss` returns unescaped property names

[MartinWelsch]

Bug Report

Prerequisites

• [x] Can you reproduce the problem in a MWE?
• [x] Are you running the latest version of AngleSharp?
• [ ] Did you check the FAQs to see if that helps you?
• [x] Are you reporting to the correct repository? (there are multiple AngleSharp libraries, e.g., AngleSharp.Css for CSS support)
• [x] Did you perform a search in the issues?

For more information, see the CONTRIBUTING guide.

Description

Consider the followig program:

using System;
using AngleSharp;
using AngleSharp.Css.Parser;

public class Program
{
    public static void Main()
    {
        const string stylesheetText = @".className { --\/prop: value; }";
        var parser = new CssParser();
        var style = parser.ParseStyleSheet(stylesheetText);

        Console.WriteLine(style.ToCss());
        // prints:
        // .className { --/prop: value }
    }
}

The property named --/prop is written literally which results in invalid CSS.

Expected behavior: style.ToCss() to return .className { --\/prop: value }

Actual behavior: style.ToCss() returned .className { --/prop: value }

Environment details: .NET6, AngleSharp.Css 0.16.4

Possible Solution

CssProperty should escape Name using CssUtilities.Escape(Name)