add doc strings to commands missing them

Change-Id: Ib0320cc4653ff695a7ee2bad3486eeec5309d3b1

secop_psi/phytron.py

@@ -148,6 +148,7 @@ class Motor(PersistentMixin, HasIodev, Drivable):
 
     @Command
     def reset(self):
+        """reset error, set position to encoder"""
         self.read_value()
         if self.status[0] == self.Status.ERROR:
             enc = self.encoder - self.zero

secop_psi/sea.py

@@ -651,4 +651,9 @@ class SeaDrivable(SeaModule, Drivable):
 
     @Command()
     def stop(self):
+        """propagate to SEA
+
+        - on stdsct drivables this will call the halt script
+        - on EaseDriv this will set the stopped state
+        """
         self._iodev.query('%s is_running 0' % self.sea_object)

secop_psi/trinamic.py

@@ -366,6 +366,7 @@ class Motor(PersistentMixin, HasIodev, Drivable):
 
     @Command(FloatRange())
     def set_zero(self, value):
+        """adapt zero to make current position equal to given value"""
         raw = self.read_value() - self.zero
         self.write_zero(value - raw)