Under certain circumstances with Chrome, copying a diff and pasting it
in a Markdown block could format the code in a Markdown table instead of
preserving the existing format. It appears that Chrome copies each diff
row as a single table, while browsers such as Firefox create separate
tables for rows. The table detector could be fooled if the right number
of columns and rows appeared in the paste buffer.

To fix this issue, we disable the auto-table formatting if the table
originated from a diff.

Closes https://gitlab.com/gitlab-org/gitlab/-/issues/213033