fixup! Improve the timer module documentation

Author: llucax

src/frequenz/channels/timer.py

@@ -67,7 +67,7 @@ async def main() -> None:
 
 # Missed Ticks And Drifting
 
-A [`Timer`][frequenz.channels.timer.Timer]s can be used to send a messages at regular
+A [`Timer`][frequenz.channels.timer.Timer] can be used to send a messages at regular
 time intervals, but there is one fundamental issue with timers in the [asyncio][] world:
 the event loop could give control to another task at any time, and that task can take
 a long time to finish, making the time it takes the next timer message to be received
@@ -466,7 +466,7 @@ class Timer(Receiver[timedelta]):
          1 microsecond).
 
         This is to avoid floating point errors when performing calculations with time,
-        which can lead to very hard to reproduce, and debug, issues.
+        which can lead to issues that are very hard to reproduce and debug.
 
     If the timer is delayed too much, then it will behave according to the
     [`missed_tick_policy`][frequenz.channels.timer.Timer.missed_tick_policy]. Missing