symbol | in table cells

[ElenaMikhaylova]

Issue
I use markdown serializer and when symbol | is presented inside table cell node, it breaks table structure.

Repro
For example I need to serialize this table:

Current behavior
It breaks like this:

Result markdown:

 | table header 1 | table header 2 | 
 | --- |--- |
 | table cell 1 | 0 | table cell 2 | 

Expected behavior
Symbol | inside text node in table cell should not recognized as column separator