Automerge: [llvm][Docs] Release note for LLDB optionally disabled regsets for RV64 (#123363)

This PR adds the release note point for LLDB 20, discussed in
llvm/llvm-project#104547 (comment)
for the same ticket

---------

Co-authored-by: David Spickett <[email protected]>

Author: 2 people

llvm/docs/ReleaseNotes.md

@@ -488,9 +488,11 @@ Changes to LLDB
   that port to the connection handler processes. This means that only 2 ports need
   to be opened in the firewall (one for the `lldb-server` platform, one for gdbserver connections).
   In addition, due to this work, `lldb-server` now works on Windows in the server mode.
+  
+* LLDB now supports execution of user expressions for non-trivial cases for RISC-V targets, like function calls, when some code needs to be executed on the target.
 
-* LLDB now supports execution of user expressions for non-trivial cases for RISC-V
-  targets, like function calls, when some code needs to be executed on the target.
+* LLDB now supports optionally enabled/disabled register sets (particularly floating point registers) for RISC-V 64. This happens for targets like `RV64IMAC` or `RV64IMACV`,
+  that have no floating point registers. The change is applied to native debugging and core-file usage.
 
 Changes to BOLT
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