Lowercase document filters except for parameters [swashbuckle]

LowercaseDocumentFilter.cs

public class LowercaseDocumentFilter : IDocumentFilter
{
    public void Apply(SwaggerDocument swaggerDoc, DocumentFilterContext context)
    {
        swaggerDoc.Paths = swaggerDoc.Paths.ToDictionary(entry => LowercaseEverythingButParameters(entry.Key), entry => entry.Value);
    }

    private static string LowercaseEverythingButParameters(string key)
    {
        return string.Join('/', key.Split('/').Select(x => x.Contains("{") ? x : x.ToLower()));
    }
}