Replace private property with public one (dotnet#11041)

Author: am11

xml/System.Net/NetworkCredential.xml

@@ -78,7 +78,7 @@
  The <xref:System.Net.NetworkCredential> class is a base class that supplies credentials in password-based authentication schemes such as basic, digest, NTLM, and Kerberos. Classes that implement the <xref:System.Net.ICredentials> interface, such as the <xref:System.Net.CredentialCache> class, return <xref:System.Net.NetworkCredential> objects.
 
 > [!NOTE]
-> On Unix platforms, use of NTLM authentication may require installing the NTLM plugin for the GSSAPI layer used by the implemention. On Ubuntu distributions, the package is called `gss-ntlmssp`. Alternatively, applications may opt in for a managed implementation of NTLM by setting the `_UseManagedNtlm` .csproj property (.NET 9+ only), or setting the `System.Net.Security.UseManagedNtlm` AppContext switch.
+> On Unix platforms, use of NTLM authentication might require installing the NTLM plugin for the GSSAPI layer used by the implementation. On Ubuntu distributions, the package is called `gss-ntlmssp`. Alternatively, applications can opt in for a managed implementation of NTLM by setting the `System.Net.Security.UseManagedNtlm` AppContext switch or, in .NET 10 and later, the `UseManagedNtlm` MSBuild property.
 >
 > On Windows, NTLM and Negotiate (Kerberos) authentication always depend on GSSAPI of the operating system.