message: Small clarification in SEMANTICS.md about submessages error propagation
diff: @@ -244,6 +244,18 @@ intercepted by the calling contract (for `ReplyOn::Always` and
  `ReplyOn::Error`). _In this case, the messages error doesn't abort the whole
  transaction_
  +Note, that error doesn't abort the whole transaction _if and only if_ the
  +`reply` is called - so in case of `ReplyOn::Always` and `ReplyOn::Error`. If the
  +submessage is called with `ReplyOn::Success` (or `ReplyOn::Never`, which makes
  +it effectively a normal message), the error in subsequent call would result in
  +failing whole transaction and not commit the changes for it. The rule here is as
  +follows: if for any reason you want your message Handling to succeed on
  +submessage failure, you always have to reply on failure.
  +
  +Obviously - on the successful processing of sub-message, if the reply is not
  +called (in particular `ReplyOn::Error`), the whole transaction is assumed to
  +succeed, and is committed.
  +
  #### Handling the Reply
  In order to make use of `submessages`, the calling contract must have an extra
  