Fix issue #610 - odoc html-fragment not producing headings correctly
#2853
| Job | Run time |
|---|---|
| 2m 13s | |
| 2m 19s | |
| 2m 59s | |
| 7m 30s | |
| 2m 17s | |
| 2m 20s | |
| 9m 38s | |
| 4m 22s | |
| 33m 38s |