Merge bitcoin/bitcoin#25237: rpc: Capture UniValue by ref for rpcdoccheck

20ff499 rpc: Capture potentially large UniValue by ref for rpcdoccheck (Martin Zumsande)

Pull request description:

  Capturing it by reference instead of value should save us from making a copy of a potentially large object. Saw this while having a look at #25229 although I couldn't reproduce an actual leak, so this is not a fix for that issue.

ACKs for top commit:
  MarcoFalke:
    review ACK 20ff499
  theStack:
    Code-review ACK 20ff499
  furszy:
    Code ACK 20ff499

Tree-SHA512: faf7bb14e37f8324b93a39095b07693626329da47c4a1ac8929bf99385e2e0567008e959e7e8540bc7d454d08fa41cccd39f55253c9a839fa88362922058a93b

Author: fanquake

src/rpc/util.cpp

@@ -583,7 +583,7 @@ UniValue RPCHelpMan::HandleRequest(const JSONRPCRequest& request) const
     }
     const UniValue ret = m_fun(*this, request);
     if (gArgs.GetBoolArg("-rpcdoccheck", DEFAULT_RPC_DOC_CHECK)) {
-        CHECK_NONFATAL(std::any_of(m_results.m_results.begin(), m_results.m_results.end(), [ret](const RPCResult& res) { return res.MatchesType(ret); }));
+        CHECK_NONFATAL(std::any_of(m_results.m_results.begin(), m_results.m_results.end(), [&ret](const RPCResult& res) { return res.MatchesType(ret); }));
     }
     return ret;
 }