Move IsPeerAddrLocalGood() declaration from header to implementation

src/net.cpp

@@ -223,7 +223,7 @@ static int GetnScore(const CService& addr)
 }
 
 // Is our peer's addrLocal potentially useful as an external IP source?
-bool IsPeerAddrLocalGood(CNode *pnode)
+[[nodiscard]] static bool IsPeerAddrLocalGood(CNode *pnode)
 {
     CService addrLocal = pnode->GetAddrLocal();
     return fDiscover && pnode->addr.IsRoutable() && addrLocal.IsRoutable() &&

src/net.h

@@ -145,7 +145,6 @@ enum
     LOCAL_MAX
 };
 
-bool IsPeerAddrLocalGood(CNode *pnode);
 /** Returns a local address that we should advertise to this peer. */
 std::optional<CService> GetLocalAddrForPeer(CNode& node);