[SYCL][Docs] Clarify virtual memory accessibility (#20576)

This commit adds wording specifying that access mode applies to all
devices in the context for which the corresponding memory is accessible.

---------

Signed-off-by: Larsen, Steffen <[email protected]>

Author: steffenlarsen

sycl/doc/extensions/experimental/sycl_ext_oneapi_virtual_mem.asciidoc

@@ -298,6 +298,12 @@ the returned pointer is accessible after the call as read-only or read-write
 respectively. Otherwise, it is considered inaccessible and accessing it will
 result in undefined behavior.
 
+If other devices in the context associated with this instance of `physical_mem`
+have enabled peer-to-peer access with the device associated with this instance
+of `physical_mem` via link:../supported/sycl_ext_oneapi_peer_access.asciidoc[
+sycl_ext_oneapi_peer_access], those other devices also have access to this
+mapped memory, and the access mode applies to accesses from those devices also.
+
 The returned pointer is equivalent to `reinterpret_cast<void *>(ptr)`.
 
 Writing to any address in the virtual memory range with access mode set to
@@ -353,6 +359,12 @@ If `mode` is `address_access_mode::read` or `address_access_mode::read_write`
 respectively. Otherwise, it is considered inaccessible and accessing it will
 result in undefined behavior.
 
+If other devices in `syclContext` have enabled peer-to-peer access with the
+device on which the memory referenced by `ptr` resides via
+link:../supported/sycl_ext_oneapi_peer_access.asciidoc[
+sycl_ext_oneapi_peer_access], those other devices also have access to this
+mapped memory, and the access mode applies to accesses from those devices also.
+
 The virtual memory range specified by `ptr` and `numBytes` must be a sub-range
 of virtual memory ranges previously mapped to `physical_mem`. `ptr`
 must be aligned to the minimum memory granularity of the device associated with