Text correction of timer.rst (#8074)

* Update timer.rst

Changed text because of an inconsistence between title and text explaining the timerGetConfig function.
I don't know if the method timerSetConfig really exists.

* Update timer.rst

Add informations about timerSetConfig function.

docs/source/api/timer.rst

@@ -48,10 +48,10 @@ This function is used to end timer.
 
 * ``timer`` timer struct.
 
-timerSetConfig
+timerGetConfig
 **************
 
-This function is used to configure initialized timer (timerBegin() called).
+This function is used to get configuration of initialized timer (timerBegin() called).
 
 .. code-block:: arduino
 
@@ -62,6 +62,18 @@ This function is used to configure initialized timer (timerBegin() called).
 This function will return ``configuration`` as uint32_t number. 
 This can be translated by inserting it to struct ``timer_cfg_t.val``.
 
+timerSetConfig
+**************
+
+This function is used to configure initialized timer (timerBegin() called).
+
+.. code-block:: arduino
+
+    void timerSetConfig(hw_timer_t *timer, uint32_t config);
+
+* ``timer`` timer struct.
+* ``config`` configuration as uint32_t number. Use configuration struct ``timer_cfg_t`` and pass ``timer_cfg_t.val`` as ``config`` paramater.
+
 timerAttachInterrupt
 ********************