Add get_allocator() to sampled_image

Author: Pennycook

adoc/chapters/programming_interface.adoc

@@ -6741,6 +6741,13 @@ size_t byte_size() const noexcept
       due to padding of elements, rows and slices of the image for
       efficient access.
 
+a@
+[source]
+----
+AllocatorT get_allocator() const
+----
+   a@ Returns the allocator provided to the image.
+
 a@
 [source]
 ----

adoc/headers/sampledImage.h

@@ -53,6 +53,8 @@ class sampled_image {
 
   size_t size() const noexcept;
 
+  AllocatorT get_allocator() const;
+
   template <typename DataT, image_target Targ = image_target::device>
   sampled_image_accessor<DataT, Dimensions, Targ>
   get_access(handler& commandGroupHandler, const property_list& propList = {});