Improve RandomNumberGenerator documentation to prefer static APIs

[vcsjones]

Summary

The RandomNumberGenerator class is currently documented as a base class which other random number generators should derive from, and that callers are expected to use a derived class.

We've de-emphasized using derived classes for RandomNumberGenerator, going so far as to obsolete the only in-box derived type, RNGCryptoServiceProvider.

These changes attempt to steer people toward using the new static APIs, instead of Create or derived types.

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Issue Details

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Summary

The RandomNumberGenerator class is currently documented as a base class which other random number generators should derive from, and that callers are expected to use a derived class.

We've de-emphasized using derived classes for RandomNumberGenerator, going so far as to obsolete the only in-box derived type, RNGCryptoServiceProvider.

These changes attempt to steer people toward using the new static APIs, instead of Create or derived types.

Author:	vcsjones
Assignees:	-
Labels:	area-System.Security
Milestone:	-

[opbld30]

Docs Build status updates of commit 98ef492:

✅ Validation status: passed

File	Status	Preview URL	Details
xml/System.Security.Cryptography/RandomNumberGenerator.xml	✅Succeeded	View

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