fix(qsl): print "TNX QSL" rather than "TNX" on the card

The stamp answers "PSE QSL", so it reads as its counterpart or not at all: a
bare "TNX" next to a QSL message says thanks for something unnamed.

Changed at the source of the {qso.pse_tnx} token, so every card picks it up
with no template edit. The live indicator in the QSO editor and the hint beside
it follow.

app_qsl_designer.go

@@ -41,7 +41,7 @@ const appQSLCardSentField = "APP_OPSLOG_QSL_SENT"
 
 // appQSLCardRcvdField marks that a QSL was RECEIVED for this QSO (set by the
 // operator, e.g. when a card arrives by e-mail). It drives the PSE/TNX stamp on
-// the card: received → "TNX" (thanks for your card), not received → "PSE QSL"
+// the card: received → "TNX QSL" (thanks for your card), not received → "PSE QSL"
 // (please send one). Independent of ADIF qsl_rcvd, like the sent field.
 const appQSLCardRcvdField = "APP_OPSLOG_QSL_RCVD"
 
@@ -681,7 +681,7 @@ func (a *App) qslVars(q qso.QSO) (map[string]string, qslcard.CountryInfo, error)
 	// QSO (appQSLCardRcvdField): received → thank them, otherwise ask for a card.
 	pseTnx := "PSE QSL"
 	if q.Extras != nil && strings.TrimSpace(q.Extras[appQSLCardRcvdField]) != "" {
-		pseTnx = "TNX"
+		pseTnx = "TNX QSL"
 	}
 	vars := map[string]string{
 		"profile.callsign":      info.Callsign,