libpq: Trace all NegotiateProtocolVersion fields

Previously, the names of the unsupported protocol options were not
traced. Since NegotiateProtocolVersion has not really been used yet,
that has not mattered much, but we hope to use it eventually, so let's
fix this.

Author: Jelte Fennema-Nio <postgres@jeltef.nl>
Discussion: https://postgr.es/m/CAGECzQTfc_O+HXqAo5_-xG4r3EFVsTefUeQzSvhEyyLDba-O9w@mail.gmail.com

Author: robertmhaas

src/interfaces/libpq/fe-trace.c

@@ -578,9 +578,15 @@ pqTraceOutput_RowDescription(FILE *f, const char *message, int *cursor, bool reg
 static void
 pqTraceOutput_NegotiateProtocolVersion(FILE *f, const char *message, int *cursor)
 {
+	int			nparams;
+
 	fprintf(f, "NegotiateProtocolVersion\t");
 	pqTraceOutputInt32(f, message, cursor, false);
-	pqTraceOutputInt32(f, message, cursor, false);
+	nparams = pqTraceOutputInt32(f, message, cursor, false);
+	for (int i = 0; i < nparams; i++)
+	{
+		pqTraceOutputString(f, message, cursor, false);
+	}
 }
 
 static void