Update NuGet package description (#1973)

Make the description clear that it is a replacement for SDS and is the latest library for SQL connectivity.

tools/specs/Microsoft.Data.SqlClient.nuspec

@@ -10,7 +10,7 @@
     <projectUrl>https://aka.ms/sqlclientproject</projectUrl>
     <icon>dotnet.png</icon>
     <repository type="git" url="https://github.com/dotnet/sqlclient" />
-    <description>Provides the data provider for SQL Server. These classes provide access to versions of SQL Server and encapsulate database-specific protocols, including tabular data stream (TDS)
+    <description>The current data provider for SQL Server and Azure SQL databases. This has replaced System.Data.SqlClient. These classes provide access to SQL and encapsulate database-specific protocols, including tabular data stream (TDS).
 
 Commonly Used Types:
 Microsoft.Data.SqlClient.SqlConnection