Add release note for parallel module creation in LLDB

Release note llvm#110646 and llvm#114507.

Author: JDevlieghere

llvm/docs/ReleaseNotes.md

@@ -355,6 +355,8 @@ Changes to LLDB
 
 * A new setting `target.launch-working-dir` can be used to set a persistent cwd that is used by default by `process launch` and `run`.
 
+* LLDB now creates modules in parallel, resulting in an average 2x speedup when launching and attaching.
+
 Changes to BOLT
 ---------------------------------