Update obsolete crypto API remarks and exceptions

[gewarren]

(Hide whitespace changes in diff.)

Contributes to dotnet/docs#20995.

[opbld32]

Docs Build status updates of commit b69931a:

✅ Validation status: passed

File	Status	Preview URL	Details
xml/System.Security.Cryptography/AsymmetricAlgorithm.xml	✅Succeeded	View
xml/System.Security.Cryptography/HMAC.xml	✅Succeeded	View
xml/System.Security.Cryptography/HashAlgorithm.xml	✅Succeeded	View
xml/System.Security.Cryptography/KeyedHashAlgorithm.xml	✅Succeeded	View
xml/System.Security.Cryptography/SymmetricAlgorithm.xml	✅Succeeded	View

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