Reset s:fuzzy for star-search

After a fuzzy-search (e.g. `z/foo`), a star-search (e.g. let `<cword>` be `bar`) results in `s:echo_pattern` outputting `F/foo` instead of `/\V\<bar\>`. Also, if all matches are removed from the buffer and the star-search is then repeated with `n` or `N`, `s:e486_fuzzy` outputs `E486: Fuzzy pattern not found: foo`.

Both of these issues are fixed by setting `s:fuzzy` to `0` in `s:star_search`.