Try and make the closing callsign appear.

(cherry picked from commit 063b21f999)

FM.cpp

@@ -316,7 +316,7 @@ void CFM::stateMachine(bool validRFSignal, bool validExtSignal)
       break;
   }
 
-  if (m_state == FS_LISTENING && !m_rfAck.isRunning() && !m_extAck.isRunning()) {
+  if (m_state == FS_LISTENING && !m_rfAck.isWanted() && !m_extAck.isWanted() && !m_callsign.isWanted()) {
     m_outputRFRB.reset();
     m_downsampler.reset();
   }

FMKeyer.cpp

@@ -205,6 +205,11 @@ void CFMKeyer::stop()
   m_audioPos = 0U;
 }
 
+bool CFMKeyer::isWanted() const
+{
+  return m_wanted;
+}
+
 bool CFMKeyer::isRunning() const
 {
   return m_poPos > 0U || m_dotPos > 0U || m_audioPos > 0U;

FMKeyer.h

@@ -35,6 +35,8 @@ public:
 
   bool isRunning() const;
 
+  bool isWanted() const;
+
 private:
   bool     m_wanted;
   uint8_t  m_poBuffer[1000U];