Merge bitcoin/bitcoin#34986: docs: remove duplicate ///@} from bitcoinkernel.h

7abf6f6 docs: remove duplicate ///@} from bitcoinkernel.h (Alexander Wiederin)

Pull request description:

  ### Summary

  Removes a redundant **group end marker** in the kernel API docs.

  ### Motivation

  Cleans kernel API documentation.

ACKs for top commit:
  maflcko:
    lgtm ACK 7abf6f6
  kevkevinpal:
    ACK [7abf6f6](bitcoin/bitcoin@7abf6f6)
  theStack:
    ACK 7abf6f6

Tree-SHA512: a5b9895c2f2bbce7a13197ab18e4f1fafe3e27062f16d63a077cd6b8633f5c82014167f7bb3142217f772a96fc3b41be49d0753e6ef8e0693afe59d030c74432

Author: hebasto

src/kernel/bitcoinkernel.h

@@ -1610,8 +1610,6 @@ BITCOINKERNEL_API void btck_txid_destroy(btck_Txid* txid);
 
 ///@}
 
-///@}
-
 /** @name Coin
  * Functions for working with coins.
  */