Made word selection match the way sheckspell highlights words
Qt treats symbols like ' and - as some kind of separate words, so if you try to
select "it's" as a word with QTextCursor, you would get either "it", "'" or "s",
depending on where your QTextCursor is. Same for the hyphen and other symbols.
With this commit I have made it treat words containing ' and - as a single word.