Fix a typo in the HashAlgorithm example. (dotnet#7391)

The example uses SHA-256 but the caption says it uses SHA1CryptoServiceProvider.

Author: teo-tsirpanis

xml/System.Security.Cryptography/HashAlgorithm.xml

@@ -69,7 +69,7 @@
  Due to collision problems with SHA1, Microsoft recommends a security model based on SHA256 or better.
 
 ## Examples
- The following code example computes the <xref:System.Security.Cryptography.SHA1CryptoServiceProvider> hash for an array. This example assumes that there is a predefined byte array `dataArray[]`. <xref:System.Security.Cryptography.SHA1CryptoServiceProvider> is a derived class of <xref:System.Security.Cryptography.HashAlgorithm>.
+ The following code example computes the <xref:System.Security.Cryptography.SHA256> hash for an array. This example assumes that there is a predefined byte array `dataArray[]`. <xref:System.Security.Cryptography.SHA256> is a derived class of <xref:System.Security.Cryptography.HashAlgorithm>.
 
  :::code language="cpp" source="~/samples/snippets/cpp/VS_Snippets_CLR_Classic/classic HashAlgorithm Example/CPP/source.cpp" id="Snippet1":::
  :::code language="csharp" source="~/samples/snippets/csharp/VS_Snippets_CLR_Classic/classic HashAlgorithm Example/CS/source.cs" id="Snippet1":::