Adapt sim_* cfg's to current syntax

+ make 'limit' usable as type in cfg files
+ minor fixes

Change-Id: Ib94b2645c7a0d978d64d4c86c4415d4b5b0d485f
Reviewed-on: https://forge.frm2.tum.de/review/c/sine2020/secop/playground/+/21485
Tested-by: Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>
Tested-by: JenkinsCodeReview <bjoern_pedersen@frm2.tum.de>
Reviewed-by: Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>

secop_demo/cryo.py

@@ -134,8 +134,7 @@ class Cryostat(CryoBase):
     )
     commands = dict(
         stop=Override(
-            "Stop ramping the setpoint\n\nby setting the current setpoint as new target",
-            special='content of special property'),
+            "Stop ramping the setpoint\n\nby setting the current setpoint as new target"),
     )
 
     def initModule(self):