Remove unnecessary "is"

Co-authored-by: Andrey Alekseenko <[email protected]>

adoc/extensions/sycl_khr_free_function_commands.adoc

@@ -479,7 +479,7 @@ _Preconditions_:
   accessible on the device;
 * [code]#src# and [code]#dest# both point to allocations of at least
   [code]#count# elements of type [code]#T#; and
-* If either [code]#src# or [code]#dest# is a pointer is to a USM allocation,
+* If either [code]#src# or [code]#dest# is a pointer to a USM allocation,
   that allocation was created from the same context as the handler's queue.
 
 _Effects (1)_: Equivalent to [code]#h.copy(src, dest, count)#.