Merge #17743: doc: Add release note for RPC Whitelist

7965e0b doc: Add release note for RPC Whitelist (Emil Engler)

Pull request description:

  A release note for #12763

ACKs for top commit:
  laanwj:
    ACK 7965e0b

Tree-SHA512: 4ac3e62029a403e64e4cd3183433dc7aa071d42688b689d7cffb8f08dc4b26d2a586d32fa791d2b5679d6b95cd6e34c56e40a5592b9af446ad9429307f7267fe

Author: laanwj

doc/release-notes.md

@@ -78,6 +78,9 @@ New RPCs
 New settings
 ------------
 
+- RPC Whitelist system. It can give certain RPC users permissions to only some RPC calls.
+It can be set with two command line arguments (`rpcwhitelist` and `rpcwhitelistdefault`). (#12763)
+
 Updated settings
 ----------------