Add release notes for listdescriptors RPC

Original PR is #20226

Author: S3RK

doc/release-notes.md

@@ -93,6 +93,10 @@ Tools and Utilities
 Wallet
 ------
 
+- A new `listdescriptors` RPC is available to inspect the contents of descriptor-enabled wallets.
+  The RPC returns public versions of all imported descriptors, including their timestamp and flags.
+  For ranged descriptors, it also returns the range boundaries and the next index to generate addresses from. (#20226)
+
 GUI changes
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