Fix ValueTuple<T7> Description (#2811)

"eight or more elements" -> "seven elements"

Author: nogic1008

xml/System/ValueTuple`7.xml

@@ -74,13 +74,13 @@
       <format type="text/markdown"><![CDATA[  
   
 ## Remarks  
- A value tuple is a data structure that has a specific number and sequence of values. The <xref:System.ValueTuple%607> structure represents a value tuple that has eight or more elements.  
+ A value tuple is a data structure that has a specific number and sequence of values. The <xref:System.ValueTuple%607> structure represents a value tuple that has seven elements.  
   
  The value tuple types differ from the tuple types (such as <xref:System.Tuple%607>) as follows:  
   
 -   They are structures (value types) rather than classes (reference types).  
   
--   Members such as <xref:System.ValueTuple%607.Item1> and   <xref:System.ValueTuple%607.Item2> are fields rather than properties.  
+-   Members such as <xref:System.ValueTuple%607.Item1> and <xref:System.ValueTuple%607.Item2> are fields rather than properties.  
   
 -   Their fields are mutable rather than read-only.  
   
@@ -950,4 +950,4 @@ The <xref:System.ValueTuple%607> type is not serializable in .NET Core 1.x or in
       </Docs>
     </Member>
   </Members>
-</Type>
+</Type>