Change a comment on NonNullableReferenceTypesAsRequired

The new comment true to what is actually done when setting this option.

src/Swashbuckle.AspNetCore.SwaggerGen/DependencyInjection/SwaggerGenOptionsExtensions.cs

@@ -310,7 +310,7 @@ public static void SupportNonNullableReferenceTypes(this SwaggerGenOptions swagg
         }
 
         /// <summary>
-        /// Enable detection of non nullable reference types to set Required flag accordingly on schema properties
+        /// Enable detection of non nullable reference types to mark the member as required in schema properties
         /// </summary>
         /// <param name="swaggerGenOptions"></param>
         public static void NonNullableReferenceTypesAsRequired(this SwaggerGenOptions swaggerGenOptions)