Column grows wider every markdown-cycle if a cell ends in `\|`

[tspiteri]

Steps to Reproduce

1. In a markdown file insert the text | x \| | which is a table with one cell.
2. Cycle to the next cell using TAB.

An extra space is added to the cell while it shouldn't.

Software Versions

;; Version: 2.4-dev
;; Package-Version: 20200514.16

[syohex]

I have merged #490. Please check latest version.