Disallow newlines between phase and identifier

[lucacasonato]

There is a cross cutting concern with module declarations:

module source {}
import source
x
from
"url"

Here it is ambiguous whether this is:

module source {}
import source;
x;
from;
"url";

or

import source x from "url";

We should disambiguate by banning newlines after <phase> in the static syntax.

Thanks @hax for reporting!

[lucacasonato]

@waldemarhorwat You may be interested in this issue too.