plugins/python/example_{io,conversation}: avoid printing signal number

They are platform dependant, so their test would fail on some platforms.
While we could create separate plugin for the tests, I like the idea that
the examples are ensured to be working.

I believe this is a good compromise for being able to auto update the
test cases.

plugins/python/example_io_plugin.py

@@ -99,8 +99,7 @@ class SudoIOPlugin(sudo.Plugin):
 
     def log_suspend(self, signo: int) -> int:
         try:
-            signal_name = signal.Signals(signo).name
-            signal_description = "{} ({})".format(signal_name, signo)
+            signal_description = signal.Signals(signo).name
         except (AttributeError, ValueError):
             signal_description = "signal {}".format(signo)