Improve the jerry port api documents. (#4977)

Notable changes:
  - Remove the comments in port impl, that's easily getting to in-consistence
  - Sync the jerryscript-port.h and 05.PORT-API.md
  - Fixes the invalid comment in port codes

JerryScript-DCO-1.0-Signed-off-by: Yonggang Luo luoyonggang@gmail.com

docs/05.PORT-API.md

@@ -119,6 +119,8 @@ void jerry_port_context_free (void);
  *
  * The implementation can decide whether error and debug messages are logged to
  * the console, or saved to a database or to a file.
+ *
+ * @param message_p: the message to log.
  */
 void jerry_port_log (const char *message_p);
 ```