rpc: Capture potentially large UniValue by ref for rpcdoccheck

Github-Pull: 25237
Rebased-From: 20ff499

Author: mzumsande

src/rpc/util.cpp

@@ -573,7 +573,7 @@ UniValue RPCHelpMan::HandleRequest(const JSONRPCRequest& request) const
         throw std::runtime_error(ToString());
     }
     const UniValue ret = m_fun(*this, request);
-    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;
 }