[HAL][USART] Improve header description of USART_WaitOnFlagUntilTimeout() function

Src/stm32l0xx_hal_usart.c

diff --git a/Src/stm32l0xx_hal_usart.c b/Src/stm32l0xx_hal_usart.c
index 69d40c1..e00bd2a 100644
--- a/Src/stm32l0xx_hal_usart.c
+++ b/Src/stm32l0xx_hal_usart.c
@@ -2790,10 +2790,11 @@
 
 
 /**
-  * @brief  Handle USART Communication Timeout.
+  * @brief  Handle USART Communication Timeout. It waits
+  *         until a flag is no longer in the specified status.
   * @param  husart USART handle.
   * @param  Flag Specifies the USART flag to check.
-  * @param  Status the Flag status (SET or RESET).
+  * @param  Status the actual Flag status (SET or RESET).
   * @param  Tickstart Tick start value
   * @param  Timeout timeout duration.
   * @retval HAL status