Update ValueTask`1.xml (#2005)

Author: pkulikov

xml/System.Threading.Tasks/ValueTask`1.xml

@@ -50,7 +50,7 @@ For uses other than consuming the result of an asynchronous operation using awai
 As such, the default choice for any asynchronous method should be to return a <xref:System.Threading.Tasks.Task> or <xref:System.Threading.Tasks.Task%601>. Only if performance analysis proves it worthwhile should a <xref:System.Threading.Tasks.ValueTask%601> be used instead of a <xref:System.Threading.Tasks.Task%601>. There is no non-generic version of <xref:System.Threading.Tasks.ValueTask%601>, as the <xref:System.Threading.Tasks.Task.CompletedTask> property may be used to hand back a successfully completed singleton in the case where a method returning a <xref:System.Threading.Tasks.Task> completes synchronously and successfully.   
 
 > [!NOTE]
->  The use of the <xref:System.Threading.Tasks.ValueTask%601> type is supported starting with C# 7, and is not supported by any version of Visual Basic.
+>  The use of the <xref:System.Threading.Tasks.ValueTask%601> type is supported starting with C# 7.0, and is not supported by any version of Visual Basic.
  ]]></format>
     </remarks>
   </Docs>
@@ -623,4 +623,4 @@ As such, the default choice for any asynchronous method should be to return a <x
       </Docs>
     </Member>
   </Members>
-</Type>
+</Type>