RCS1142: Add 'typeparam' element to documentation comment

Example

/// <summary>
/// ...
/// </summary>
/// <typeparam name="T1"></typeparam>
public class Foo<T1, T2> // RCS1142
{
}

/// <summary>
/// ...
/// </summary>
/// <typeparam name="T1"></typeparam>
/// <typeparam name="T2"></typeparam>
public class Foo<T1, T2>
{
}