[Fix] Resonator longitudinal wake function

mbtrack2/impedance/resonator.py

@@ -98,7 +98,7 @@ class Resonator(WakeField):
                    (2 * self.Q_p)))
         if np.any(np.abs(t) < atol):
             wl[np.abs(t) < atol] = wl[np.abs(t) < atol] / 2
-        elif np.any(t < -atol):
+        if np.any(t < -atol):
             wl[t < -atol] = 0
         return wl