We currently use the debug representation of Span to know if they are
next touching eachother as there are no stable way currently.
But that doesn't work with rust analyzer as it doesn't have a
representation we can test.
Also Span::source_text is not implemented with rust analyzer.

So just default to identifier with `-` touching instead of not touching
as this happens more often.

One can still use `(foo)-(bar)` when one really need minus

CC #685