Update DoesNotReturnAttribute.xml (#9329)

Removed redundant and incorrect second "that" in DoesNotReturnAttribute summary.

Author: SamuelMoisan98

xml/System.Diagnostics.CodeAnalysis/DoesNotReturnAttribute.xml

@@ -35,7 +35,7 @@
     </Attribute>
   </Attributes>
   <Docs>
-    <summary>Specifies that a method that will never return under any circumstance.</summary>
+    <summary>Specifies that a method will never return under any circumstance.</summary>
     <remarks>For more information, see <see href="/dotnet/csharp/language-reference/attributes/nullable-analysis">Nullable static analysis</see> in the C# guide.</remarks>
     <related type="Article" href="/dotnet/csharp/language-reference/attributes/nullable-analysis">Nullable static analysis</related>
   </Docs>