[FEATURE] Support Sphinx's table spans

[dkd-kaehm]

Feature request

The table spans are currently not supported, neither for grid tables nor for simple tables syntax.

Simple table syntax: See (Sphinx docs link):

=====  =====  ======
   Inputs     Output
------------  ------
  A      B    A or B
=====  =====  ======
False  False  False
True   False  True
False  True   True
True   True   True
=====  =====  ======

Produces currently:

---

Grid table syntax: See (Sphinx docs link):

+--------------+----------+-----------+-----------+
| row 1, col 1 | column 2 | column 3  | column 4  |
+--------------+----------+-----------+-----------+
| row 2        |                                  |
+--------------+----------+-----------+-----------+
| row 3        |          |           |           |
+--------------+----------+-----------+-----------+

Produces currently: