DataRows SetModified and SetAdded is not the same between the code and the document

[ThoaiLeOrangelogic]

https://github.com/dotnet/runtime/blame/5535e31a712343a63f5d7d796cd874e563e5ac14/src/libraries/System.Data.Common/src/System/Data/DataRow.cs#L1378C13-L1391C10

The document said that (https://learn.microsoft.com/en-us/dotnet/api/system.data.datarow.setmodified?view=net-8.0)

But in the code it only available for RowState.Unchanged

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[roji]

The documentation remark itself seems to contradict itself: on the one hand, it says that an exception is thrown "if the current row is not in either an Unchanged or an Added state. On the other hand, the exception message is supposed to says that SetModifiedcan only be invoked on aDataRowinstance where theRowStateisUnchanged" (Added` is missing).

As pointed out above, the actual code is to only allow calling SetModified when the state is Unchanged, and to throw otherwise; I'm guessing the behavior was changed at some point but the documentation was left in an out-of-sync/contradictory state.

Submitted dotnet/dotnet-api-docs#10323 to amend the docs.