Fix copy-paste error in MemoryMarshal.TryWrite (#2805)

Author: Zenexer

xml/System.Runtime.InteropServices/MemoryMarshal.xml

@@ -989,7 +989,7 @@ This method allows a read-only memory buffer to be used in existing APIs that re
        ]]></format>
         </remarks>
         <exception cref="T:System.ArgumentException">
-          <paramref name="TFrom" /> or <paramref name="TTo" /> contains references or pointers.</exception>
+          <paramref name="T" /> contains references or pointers.</exception>
       </Docs>
     </Member>
     <Member MemberName="Write&lt;T&gt;">
@@ -1047,4 +1047,4 @@ This method allows a read-only memory buffer to be used in existing APIs that re
       </Docs>
     </Member>
   </Members>
-</Type>
+</Type>