[lldb] Add non-address bit improvements to release notes

This summarises the changes made by d9398a9.
Which forms the bulk of the fixes needed for non-address bit handling.

Note that in the previous releases we noted memory tagging support,
which is a subset of non-address bits. The recent changes enable
debugging of programs using memory tagging, pointer authentication
and top byte ignore (all at once) on AArch64.

Author: DavidSpickett

llvm/docs/ReleaseNotes.rst

@@ -179,6 +179,18 @@ Changes to LLDB
 * Added "--show-tags" option to the "memory find" command. This is off by default.
   When enabled, if the target value is found in tagged memory, the tags for that
   memory will be shown inline with the memory contents.
+* Various memory related parts of LLDB have been updated to handle
+  non-address bits (such as AArch64 pointer signatures):
+
+  * "memory read", "memory write" and "memory find" can now be used with
+    addresses with non-address bits.
+  * All the read and write memory methods on SBProccess and SBTarget can
+    be used with addreses with non-address bits.
+  * When printing a pointer expression, LLDB can now dereference the result
+    even if it has non-address bits.
+  * The memory cache now ignores non-address bits when looking up memory
+    locations. This prevents us reading locations multiple times, or not
+    writing out new values if the addresses have different non-address bits.
 
 Changes to Sanitizers
 ---------------------