`a *b* c` would be matched by `(?<=\\s)(\\*[^\\*]+\\*)`, but wouldn't by `(?<=^)(\\*[^\\s\\*][^\\*]*\\*)`. This is covered by [this test](https://github.com/atom/language-gfm/blob/801994dab6bf230de106dc01b157c01ca9e39b64/spec/gfm-spec.coffee#L63) I believe.