QHexDocument::searchForward does not move the cursor past the first result

[JonTheBurger]

Once searchForward finds a result, subsequent calls to searchForward do not move the cursor. searchBackward does move the cursor in its analogous case.

https://github.com/Dax89/QHexView/blob/4d06da87e7e9202d1d760afaee6f4a4b297612fc/document/qhexdocument.cpp#L175 I believe this line needs a +1 (and maybe hasSelection handling like searchBackward does?)