Add release note for parallel module creation in LLDB (#116857)

Release note #110646 and #114507.

Author: JDevlieghere

llvm/docs/ReleaseNotes.md

@@ -356,6 +356,8 @@ 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 parses shared libraries in parallel, resulting in an average 2x speedup when attaching (only available on Darwin platforms) and launching (available on all platforms).
+
 Changes to BOLT
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