fix: move CGovernanceVote inline methods to header for wallet linkage

The methods GetSignatureString() and GetSignatureHash() were only available
in libbitcoin_node.a but were being called from wallet.cpp. This caused
undefined reference errors when linking dash-wallet since it doesn't link
against libbitcoin_node.

Moving these simple methods to the header as inline functions resolves
the linking issue without requiring wallet binaries to link against the
entire node library.

Author: PastaPastaPasta

src/governance/vote.cpp

@@ -140,10 +140,6 @@ uint256 CGovernanceVote::GetHash() const
     return hash;
 }
 
-uint256 CGovernanceVote::GetSignatureHash() const
-{
-    return SerializeHash(*this);
-}
 
 bool CGovernanceVote::CheckSignature(const CKeyID& keyID) const
 {
@@ -218,13 +214,6 @@ bool CGovernanceVote::IsValid(const CDeterministicMNList& tip_mn_list, bool useV
     }
 }
 
-std::string CGovernanceVote::GetSignatureString() const
-{
-    return masternodeOutpoint.ToStringShort() + "|" + nParentHash.ToString() + "|" +
-                             ::ToString(nVoteSignal) + "|" +
-                             ::ToString(nVoteOutcome) + "|" +
-                             ::ToString(nTime);
-}
 
 bool operator==(const CGovernanceVote& vote1, const CGovernanceVote& vote2)
 {

src/governance/vote.h

@@ -5,8 +5,10 @@
 #ifndef BITCOIN_GOVERNANCE_VOTE_H
 #define BITCOIN_GOVERNANCE_VOTE_H
 
+#include <hash.h>
 #include <primitives/transaction.h>
 #include <uint256.h>
+#include <util/string.h>
 
 class CActiveMasternodeManager;
 class CBLSPublicKey;
@@ -100,7 +102,13 @@ class CGovernanceVote
     bool Sign(const CActiveMasternodeManager& mn_activeman);
     bool CheckSignature(const CBLSPublicKey& pubKey) const;
     bool IsValid(const CDeterministicMNList& tip_mn_list, bool useVotingKey) const;
-    std::string GetSignatureString() const;
+    std::string GetSignatureString() const
+    {
+        return masternodeOutpoint.ToStringShort() + "|" + nParentHash.ToString() + "|" +
+                                 ::ToString(nVoteSignal) + "|" +
+                                 ::ToString(nVoteOutcome) + "|" +
+                                 ::ToString(nTime);
+    }
     void Relay(PeerManager& peerman, const CMasternodeSync& mn_sync, const CDeterministicMNList& tip_mn_list) const;
 
     const COutPoint& GetMasternodeOutpoint() const { return masternodeOutpoint; }
@@ -112,7 +120,10 @@ class CGovernanceVote
     */
 
     uint256 GetHash() const;
-    uint256 GetSignatureHash() const;
+    uint256 GetSignatureHash() const
+    {
+        return SerializeHash(*this);
+    }
 
     std::string ToString(const CDeterministicMNList& tip_mn_list) const;