rpc: Move ValueFromAmount to core_write

This is necessary because core_write has to write amounts in
TxToUniv, and mistakingly uses FormatMoney for that
(which is only for debugging).

We don't move AmountFromValue at the same time, as
this is more challenging due to the RPCError depencency
there.

src/core_io.h

@@ -5,6 +5,8 @@
 #ifndef BITCOIN_CORE_IO_H
 #define BITCOIN_CORE_IO_H
 
+#include "amount.h"
+
 #include <string>
 #include <vector>
 
@@ -25,6 +27,7 @@ uint256 ParseHashStr(const std::string&, const std::string& strName);
 std::vector<unsigned char> ParseHexUV(const UniValue& v, const std::string& strName);
 
 // core_write.cpp
+UniValue ValueFromAmount(const CAmount& amount);
 std::string FormatScript(const CScript& script);
 std::string EncodeHexTx(const CTransaction& tx, const int serializeFlags = 0);
 void ScriptPubKeyToUniv(const CScript& scriptPubKey, UniValue& out, bool fIncludeHex);