sometimes merges comments where should not

looks like for short lines ## comments are pulled up, with no break, which doesnt work where the zeek parser is greedy
(or alternately i guess this is a zeek bug that the ## should have started a new comment...)
```
✦4 ❯ cat bug.zeek
@load ./foo.zeek
## @load ./bar.zeek

✦4 ❯ zeek-format bug.zeek
@load ./foo.zeek## @load ./bar.zeek
```