Combine grid table parsers

The grid table parsers for markdown and rst was combined into one single
parser, slightly changing parsing behavior of both parsers:

- The markdown parser now compactifies block content cell-wise: pure
  text blocks in cells are now treated as paragraphs only if the cell
  contains multiple paragraphs, and as plain blocks otherwise. Before,
  this was true only for single-column tables.

- The rst parser now accepts newlines and multiple blocks in header
  cells.

Closes: #3638

0 files changed, 0 insertions, 0 deletions