Make SHA algorithm names more consistent

[gewarren]

Use SHA-256 for algorithm. Use SHA256 for class name. See guidance.

(Hide whitespace changes.)

Fixes#11023. Replaces #11062.

[dotnet-policy-service]

@gewarren - This PR edits one or more files whose 'source of truth' for documentation is not in this repo. Please make documentation updates in the /// comments in the dotnet/runtime repo (or dotnet/extensions repo) instead.

[gewarren]

@gewarren - This PR edits one or more files whose 'source of truth' for documentation is not in this repo. Please make documentation updates in the /// comments in the dotnet/runtime repo (or dotnet/extensions repo) instead.

Updated in source too: dotnet/extensions#6149

[learn-build-service-prod]

Learn Build status updates of commit 6a8c940:

✅ Validation status: passed

File	Status	Preview URL	Details
xml/Microsoft.Extensions.Compliance.Redaction/HmacRedactor.xml	✅Succeeded	View
xml/System.CodeDom/CodeChecksumPragma.xml	✅Succeeded	View
xml/System.Configuration.Assemblies/AssemblyHashAlgorithm.xml	✅Succeeded	View
xml/System.IdentityModel.Tokens/InMemorySymmetricSecurityKey.xml	✅Succeeded	View
xml/System.IdentityModel.Tokens/SecurityAlgorithms.xml	✅Succeeded	View
xml/System.IdentityModel.Tokens/SymmetricSecurityKey.xml	✅Succeeded	View
xml/System.IdentityModel.Tokens/X509AsymmetricSecurityKey.xml	✅Succeeded	View
xml/System.IdentityModel/RsaEncryptionCookieTransform.xml	✅Succeeded	View
xml/System.IdentityModel/RsaSignatureCookieTransform.xml	✅Succeeded	View
xml/System.IO.Packaging/PackageDigitalSignatureManager.xml	✅Succeeded	View
xml/System.Messaging/DefaultPropertiesToSend.xml	✅Succeeded	View
xml/System.Messaging/Message.xml	✅Succeeded	View
xml/System.Net.Http.Headers/HttpContentHeaders.xml	✅Succeeded	View
xml/System.Net/HttpRequestHeader.xml	✅Succeeded	View
xml/System.Net/HttpResponseHeader.xml	✅Succeeded	View
xml/System.Reflection.Metadata/Document.xml	✅Succeeded	View
xml/System.Reflection.PortableExecutable/PdbChecksumDebugDirectoryData.xml	✅Succeeded	View
xml/System.Reflection/Assembly.xml	✅Succeeded	View
xml/System.Reflection/AssemblyHashAlgorithm.xml	✅Succeeded	View
xml/System.Security.Authentication/HashAlgorithmType.xml	✅Succeeded	View
xml/System.Security.Cryptography.Pkcs/Pkcs12Builder.xml	✅Succeeded	View
xml/System.Security.Cryptography.X509Certificates/X509Certificate.xml	✅Succeeded	View
xml/System.Security.Cryptography.Xml/Reference.xml	✅Succeeded	View
xml/System.Security.Cryptography.Xml/SignedInfo.xml	✅Succeeded	View
xml/System.Security.Cryptography.Xml/SignedXml.xml	✅Succeeded	View

This comment lists only the first 25 files in the pull request.
For more details, please refer to the build report.

For any questions, please:

• Try searching the learn.microsoft.com contributor guides
• Post your question in the Learn support channel