Fix core.UndefinedBinaryOperatorResult warning from scan-build

task-manager-linux.c:362:19: warning: The left operand of '==' is a garbage value [core.UndefinedBinaryOperatorResult]
  362 |         return (state[0] == 'T') ? TRUE : FALSE;

scan-build 17.0.6

src/task-manager-linux.c

@@ -346,7 +346,7 @@ pid_is_sleeping (GPid pid)
 	FILE *file;
 	gchar filename[96];
 	gchar buffer[1024];
-	gchar state[2];
+	gchar state[2] = { 0 };
 
 	snprintf (filename, sizeof (filename), "/proc/%i/status", pid);
 	if ((file = fopen (filename, "r")) == NULL)