bug fix in frappy_psi.convergence

+ various doc improvements

Change-Id: I8ce2a1f006a5e4870285ce1f6015510e21d01a13
Reviewed-on: https://forge.frm2.tum.de/review/c/secop/frappy/+/33906
Tested-by: Jenkins Automated Tests <pedersen+jenkins@frm2.tum.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>

frappy_psi/convergence.py

@@ -176,7 +176,7 @@ class HasConvergence:
 
     def convergence_interrupt(self, state):
         """stopping"""
-        self.__set_status(state.stop_status)  # stop called
+        self.__set_status(*state.stop_status)  # stop called
         return self.convergence_instable
 
     def stop(self):
@@ -196,3 +196,4 @@ class HasConvergence:
         if self.pollInfo:
             self.pollInfo.trigger(True)
         return value
+