Fix documentation of port API (#2312)

The patch fixes both the doc comments in the port header and the
corresponding markdown documentation.

The patch also removes an internal configuration macro guard
exposed by the public port header.

JerryScript-DCO-1.0-Signed-off-by: Akos Kiss akiss@inf.u-szeged.hu

jerry-core/include/jerryscript-port.h

@@ -114,6 +114,11 @@ typedef struct
 /**
  * Get timezone and daylight saving data
  *
+ * Note:
+ *      This port function is called by jerry-core when
+ *      CONFIG_DISABLE_DATE_BUILTIN is _not_ defined. Otherwise this function is
+ *      not used.
+ *
  * @return true  - if success
  *         false - otherwise
  */
@@ -122,6 +127,12 @@ bool jerry_port_get_time_zone (jerry_time_zone_t *tz_p);
 /**
  * Get system time
  *
+ * Note:
+ *      This port function is called by jerry-core when
+ *      CONFIG_DISABLE_DATE_BUILTIN is _not_ defined. It is also common practice
+ *      in application code to use this function for the initialization of the
+ *      random number generator.
+ *
  * @return milliseconds since Unix epoch
  */
 double jerry_port_get_current_time (void);
@@ -130,9 +141,10 @@ double jerry_port_get_current_time (void);
  * Get the current instance which contains the current context, heap and other
  * structures. Each port should provide its own implementation of this interface.
  *
- *Note:
- *    This port function is called by jerry-core when JERRY_ENABLE_EXTERNAL_CONTEXT
- *    is defined. Otherwise this function is not used.
+ * Note:
+ *      This port function is called by jerry-core when
+ *      JERRY_ENABLE_EXTERNAL_CONTEXT is defined. Otherwise this function is not
+ *      used.
  *
  * @return the pointer to the jerry instance.
  */
@@ -140,10 +152,12 @@ struct jerry_instance_t *jerry_port_get_current_instance (void);
 
 /**
  * Makes the process sleep for a given time.
+ *
+ * Note:
+ *      This port function is called by jerry-core when JERRY_DEBUGGER is
+ *      defined. Otherwise this function is not used.
  */
-#ifdef JERRY_DEBUGGER
 void jerry_port_sleep (uint32_t sleep_time);
-#endif /* JERRY_DEBUGGER */
 
 /**
  * @}