Improve IDisposable note

[gewarren]

Describe the issue or suggestion

Many types that implement IDisposable include a lengthy note block that describes how to dispose. Instead, this information should live in the IDisposable remarks only and we can simply refer readers there.

Sample of existing text:

This type implements the xref:System.IDisposable interface. When you have finished using the type, you should dispose of it either directly or indirectly. To dispose of the type directly, call its xref:System.IDisposable.Dispose* method in a try/catch block. To dispose of it indirectly, use a language construct such as using (in C#) or Using (in Visual Basic). For more information, see the "Using an Object that Implements IDisposable" section in the xref:System.IDisposable interface topic.