Merge #1045: 27.1: fix formatting in release notes

0ddea14 27.1: fix formatting in release notes (fanquake)

Pull request description:

  Not completely sure what the issue is, I guess we can't use the word Index, however this fixes the formatting of the release notes as currently shown on https://bitcoincore.org/en/releases/27.1/:
  ![Format](https://github.com/bitcoin-core/bitcoincore.org/assets/863730/119528e7-bf5a-4c9b-b89a-b9ef90ea253d)

ACKs for top commit:
  sipa:
    utACK 0ddea14

Tree-SHA512: 5a1eba0cb1b1a8ff57adf78936332f591ec7ec312ce1b6a56e773a6d87fbc80b8122a4b42af3889c9a17b6ea8b81c3da88d0e711aca3eabe866b12ff58a6e21b

Author: fanquake

_releases/27.1.md

@@ -77,7 +77,7 @@ Notable changes
 - #29870 rpc: Reword SighashFromStr error message
 - #30094 rpc: move UniValue in blockToJSON
 
-### Index
+### Indexes
 
 - #29776 Fix #29767, set m_synced = true after Commit()