docs: Minor change to improve clarity in machine.Timer docs.

docs/library/machine.Timer.rst

@@ -7,8 +7,8 @@ class Timer -- control internal timers
 
     Timers can be used for a great variety of tasks, calling a function periodically,
     counting events, and generating a PWM signal are among the most common use cases.
-    Each timer consists of 2 16-bit channels and this channels can be tied together to
-    form 1 32-bit timer. The operating mode needs to be configured per timer, but then
+    Each timer consists of two 16-bit channels and this channels can be tied together to
+    form one 32-bit timer. The operating mode needs to be configured per timer, but then
     the period (or the frequency) can be independently configured on each channel. 
     By using the callback method, the timer event can call a Python function.