Merge bitcoin/bitcoin#23284: doc: update release notes for 22539

530735153b doc: update release notes for 22539 (Antoine Poinsot)

Pull request description:

  Following Marcofalke's feedback at https://github.com/bitcoin/bitcoin/pull/22539#discussion_r724971313

ACKs for top commit:
  shaavan:
    ACK 530735153b

Tree-SHA512: 91ea3e6c7fc06a4f40723217735e3d3f12812dc5adafa4f8c505ae4df5bd91345133099a9c158a7f15f01313c3128c8c15455c24256d76cd93033c0b5ce2c64f

doc/release-notes-22539.md

@@ -1,8 +0,0 @@
-Notable changes
-===============
-
-P2P and network changes
------------------------
-
-- Fee estimation now takes the feerate of replacement (RBF) transactions into
-  account.

doc/release-notes.md

@@ -61,6 +61,12 @@ P2P and network changes
   They will become eligible for address gossip after sending an ADDR, ADDRV2,
   or GETADDR message. (#21528)
 
+Fee estimation changes
+----------------------
+
+- Fee estimation now takes the feerate of replacement (RBF) transactions into
+  account. (#22539)
+
 Rescan startup parameter removed
 --------------------------------