How to write 2-line in headers

[alisheikholeslam]

I would like to write units of the headers' parameters below them in the corresponding table cell (in the header cell, not in the rows). How could I do like that? Using \n makes it wired. e.g. if I use contacts count\n(min,max):

+-----------+--------------+-------------+-------------------------------------+----------------+---------------------+
| step name | sum of radii | sum of gaps |            gaps to radii            |        contacts count
(min,max)         | sum vol of overlaps |
+-----------+--------------+-------------+-------------------------------------+----------------+---------------------+
|  Initial  | 3.27014E+02  | 4.10990E+00 | 9.56212E-07 1.41391E-01 5.14668E-03 |     00 15      |     6.14310E-05     |

Thanks.

[hugovk]

This isn't supported, a PR is welcome.