Fix up some of the inline XML documentation
Fix some of the Argument[X] exception type messages.

Some exceptions had their arguments wrong or misspelled in some cases.

Some exceptions are [ExceptionType](paramName, message), while others are [ExceptionType](message, paramName)

This commit just fixes up some of them.
[Toolkit.Graphics] fixed memory garbage generation in PixelFormat.Equals(PixelFormat) method